diff --git a/lib/core/services/api_service.dart b/lib/core/services/api_service.dart
index c6abacf..44c217b 100644
--- a/lib/core/services/api_service.dart
+++ b/lib/core/services/api_service.dart
@@ -427,6 +427,7 @@ class ApiService {
   /// - `queryParams`: Optional query parameters
   /// - `followRedirects`: If false, will throw a [RedirectException] on 301/302 status codes.
   Future<bool> isReachable({
+    String endpoint = '/',
     Duration timeout = const Duration(seconds: 8),
   }) async {
     if (_baseUrl == null || _baseUrl!.isEmpty) return false;
@@ -437,7 +438,7 @@ class ApiService {
       httpClient.badCertificateCallback = (cert, host, port) => true;
     }
     try {
-      final uri = _buildUri(endpoint: '/');
+      final uri = _buildUri(endpoint: endpoint);
       final headers = getAuthHeaders(authMethod: AuthMethod.auto);
       if (_userAgent != null) headers['User-Agent'] = _userAgent!;
 
diff --git a/lib/core/services/connectivity_service.dart b/lib/core/services/connectivity_service.dart
index 984baf2..cc7b6e3 100644
--- a/lib/core/services/connectivity_service.dart
+++ b/lib/core/services/connectivity_service.dart
@@ -1,4 +1,5 @@
 import 'package:connectivity_plus/connectivity_plus.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 
 import 'package:calibre_web_companion/core/services/api_service.dart';
 
@@ -30,9 +31,26 @@ class ConnectivityService {
       final baseUrl = apiService.getBaseUrl();
       if (baseUrl.isEmpty) return false;
 
-      return await apiService.isReachable();
+      return await apiService.isReachable(endpoint: await _probeEndpoint());
     } catch (_) {
       return false;
     }
   }
+
+  Future<String> _probeEndpoint() async {
+    final prefs = await SharedPreferences.getInstance();
+    final override = prefs.getString('reachability_probe_endpoint')?.trim();
+    if (override != null && override.isNotEmpty) return override;
+
+    switch (prefs.getString('server_type')) {
+      case 'calibre':
+        return '/ajax/library-info';
+      case 'grimmory':
+        return '/catalog';
+      case 'opds':
+        return '';
+      default:
+        return '/ajax/listbooks?limit=1';
+    }
+  }
 }
diff --git a/lib/features/homepage/presentation/pages/home_page.dart b/lib/features/homepage/presentation/pages/home_page.dart
index 68eb045..1a72a29 100644
--- a/lib/features/homepage/presentation/pages/home_page.dart
+++ b/lib/features/homepage/presentation/pages/home_page.dart
@@ -15,7 +15,7 @@ import 'package:calibre_web_companion/features/download_service/presentation/pag
 import 'package:calibre_web_companion/features/settings/bloc/settings_bloc.dart';
 import 'package:calibre_web_companion/features/settings/bloc/settings_state.dart';
 import 'package:calibre_web_companion/features/offline/cubit/connectivity_cubit.dart';
-import 'package:calibre_web_companion/features/offline/presentation/pages/offline_library_page.dart';
+import 'package:calibre_web_companion/features/offline/presentation/pages/offline_home_page.dart';
 
 class HomePage extends StatelessWidget {
   const HomePage({super.key});
@@ -27,57 +27,13 @@ class HomePage extends StatelessWidget {
     return BlocBuilder<ConnectivityCubit, ConnectivityStatus>(
       builder: (context, connectivity) {
         if (connectivity == ConnectivityStatus.offline) {
-          return _buildOffline(context, localizations);
+          return const OfflineHomePage();
         }
         return _buildOnline(context, localizations);
       },
     );
   }
 
-  Widget _buildOffline(BuildContext context, AppLocalizations localizations) {
-    final theme = Theme.of(context);
-    return Scaffold(
-      appBar: AppBar(
-        title: Text(localizations.offline),
-        actions: [
-          IconButton(
-            icon: const Icon(Icons.refresh_rounded),
-            tooltip: localizations.retry,
-            onPressed: () => context.read<ConnectivityCubit>().recheck(),
-          ),
-        ],
-      ),
-      body: Column(
-        children: [
-          Container(
-            width: double.infinity,
-            color: theme.colorScheme.secondaryContainer,
-            padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
-            child: Row(
-              children: [
-                Icon(
-                  Icons.cloud_off_rounded,
-                  size: 20,
-                  color: theme.colorScheme.onSecondaryContainer,
-                ),
-                const SizedBox(width: 10),
-                Expanded(
-                  child: Text(
-                    localizations.offlineBannerMessage,
-                    style: theme.textTheme.bodyMedium?.copyWith(
-                      color: theme.colorScheme.onSecondaryContainer,
-                    ),
-                  ),
-                ),
-              ],
-            ),
-          ),
-          const Expanded(child: OfflineLibraryPage()),
-        ],
-      ),
-    );
-  }
-
   Widget _buildOnline(BuildContext context, AppLocalizations localizations) {
     return BlocBuilder<HomePageBloc, HomePageState>(
       builder: (context, homeState) {
diff --git a/lib/features/login/presentation/pages/login_page.dart b/lib/features/login/presentation/pages/login_page.dart
index 63af393..30e4390 100644
--- a/lib/features/login/presentation/pages/login_page.dart
+++ b/lib/features/login/presentation/pages/login_page.dart
@@ -10,6 +10,7 @@ import 'package:calibre_web_companion/features/homepage/presentation/pages/home_
 import 'package:calibre_web_companion/core/services/snackbar.dart';
 import 'package:calibre_web_companion/l10n/app_localizations.dart';
 import 'package:calibre_web_companion/features/login/presentation/widgets/login_form_widget.dart';
+import 'package:calibre_web_companion/features/offline/cubit/connectivity_cubit.dart';
 
 class LoginPage extends StatelessWidget {
   const LoginPage({super.key});
@@ -23,6 +24,7 @@ class LoginPage extends StatelessWidget {
       body: BlocListener<LoginBloc, LoginState>(
         listener: (context, state) {
           if (state.status == LoginStatus.success) {
+            context.read<ConnectivityCubit>().reportSuccess();
             Navigator.of(context).pushReplacement(
               MaterialPageRoute(builder: (context) => HomePage()),
             );
diff --git a/lib/features/login_settings/bloc/login_settings_bloc.dart b/lib/features/login_settings/bloc/login_settings_bloc.dart
index adce33c..32c4404 100644
--- a/lib/features/login_settings/bloc/login_settings_bloc.dart
+++ b/lib/features/login_settings/bloc/login_settings_bloc.dart
@@ -21,6 +21,7 @@ class LoginSettingsBloc extends Bloc<LoginSettingsEvent, LoginSettingsState> {
     on<UpdateCustomHeaderKey>(_onUpdateCustomHeaderKey);
     on<UpdateCustomHeaderValue>(_onUpdateCustomHeaderValue);
     on<UpdateBasePath>(_onUpdateBasePath);
+    on<UpdateReachabilityProbe>(_onUpdateReachabilityProbe);
     on<UpdateAllowSelfSigned>(_onUpdateAllowSelfSigned);
   }
 
@@ -34,6 +35,8 @@ class LoginSettingsBloc extends Bloc<LoginSettingsEvent, LoginSettingsState> {
       final headers = await loginSettingsRepository.getCustomHeaders();
       final basePath =
           await loginSettingsRepository.getBasePath(); // Base Path laden
+      final reachabilityProbe =
+          await loginSettingsRepository.getReachabilityProbe();
       final allowSelfSigned =
           await loginSettingsRepository.getAllowSelfSigned();
 
@@ -41,6 +44,7 @@ class LoginSettingsBloc extends Bloc<LoginSettingsEvent, LoginSettingsState> {
         state.copyWith(
           customHeaders: headers,
           basePath: basePath,
+          reachabilityProbe: reachabilityProbe,
           allowSelfSigned: allowSelfSigned,
           isLoading: false,
         ),
@@ -141,6 +145,18 @@ class LoginSettingsBloc extends Bloc<LoginSettingsEvent, LoginSettingsState> {
     }
   }
 
+  Future<void> _onUpdateReachabilityProbe(
+    UpdateReachabilityProbe event,
+    Emitter<LoginSettingsState> emit,
+  ) async {
+    emit(state.copyWith(reachabilityProbe: event.endpoint));
+    try {
+      await loginSettingsRepository.saveReachabilityProbe(event.endpoint.trim());
+    } catch (e) {
+      _logger.e('Error saving reachability probe endpoint: $e');
+    }
+  }
+
   Future<void> _onUpdateAllowSelfSigned(
     UpdateAllowSelfSigned event,
     Emitter<LoginSettingsState> emit,
diff --git a/lib/features/login_settings/bloc/login_settings_event.dart b/lib/features/login_settings/bloc/login_settings_event.dart
index 1f19319..79c1bb2 100644
--- a/lib/features/login_settings/bloc/login_settings_event.dart
+++ b/lib/features/login_settings/bloc/login_settings_event.dart
@@ -53,6 +53,15 @@ class UpdateBasePath extends LoginSettingsEvent {
   List<Object?> get props => [basePath];
 }
 
+class UpdateReachabilityProbe extends LoginSettingsEvent {
+  final String endpoint;
+
+  const UpdateReachabilityProbe(this.endpoint);
+
+  @override
+  List<Object?> get props => [endpoint];
+}
+
 class UpdateAllowSelfSigned extends LoginSettingsEvent {
   final bool allowSelfSigned;
 
diff --git a/lib/features/login_settings/bloc/login_settings_state.dart b/lib/features/login_settings/bloc/login_settings_state.dart
index 9f25206..d91ad1b 100644
--- a/lib/features/login_settings/bloc/login_settings_state.dart
+++ b/lib/features/login_settings/bloc/login_settings_state.dart
@@ -5,6 +5,7 @@ import 'package:calibre_web_companion/features/login_settings/data/models/custom
 class LoginSettingsState extends Equatable {
   final List<CustomHeaderModel> customHeaders;
   final String basePath;
+  final String reachabilityProbe;
   final bool isLoading;
   final bool isSaved;
   final bool allowSelfSigned;
@@ -13,6 +14,7 @@ class LoginSettingsState extends Equatable {
   const LoginSettingsState({
     this.customHeaders = const [],
     this.basePath = '',
+    this.reachabilityProbe = '',
     this.isLoading = false,
     this.isSaved = false,
     this.allowSelfSigned = false,
@@ -22,6 +24,7 @@ class LoginSettingsState extends Equatable {
   LoginSettingsState copyWith({
     List<CustomHeaderModel>? customHeaders,
     String? basePath,
+    String? reachabilityProbe,
     bool? isLoading,
     bool? isSaved,
     bool? allowSelfSigned,
@@ -30,6 +33,7 @@ class LoginSettingsState extends Equatable {
     return LoginSettingsState(
       customHeaders: customHeaders ?? this.customHeaders,
       basePath: basePath ?? this.basePath,
+      reachabilityProbe: reachabilityProbe ?? this.reachabilityProbe,
       isLoading: isLoading ?? this.isLoading,
       isSaved: isSaved ?? this.isSaved,
       allowSelfSigned: allowSelfSigned ?? this.allowSelfSigned,
@@ -41,6 +45,7 @@ class LoginSettingsState extends Equatable {
   List<Object?> get props => [
     customHeaders,
     basePath,
+    reachabilityProbe,
     isLoading,
     isSaved,
     allowSelfSigned,
diff --git a/lib/features/login_settings/data/datasources/login_settings_local_datasource.dart b/lib/features/login_settings/data/datasources/login_settings_local_datasource.dart
index 508937d..f395e44 100644
--- a/lib/features/login_settings/data/datasources/login_settings_local_datasource.dart
+++ b/lib/features/login_settings/data/datasources/login_settings_local_datasource.dart
@@ -18,6 +18,7 @@ class LoginSettingsLocalDataSource {
 
   static const String _customHeadersKey = 'custom_login_headers';
   static const String _basePathKey = 'base_path';
+  static const String _reachabilityProbeKey = 'reachability_probe_endpoint';
 
   Future<List<CustomHeaderModel>> getCustomHeaders() async {
     try {
@@ -75,6 +76,30 @@ class LoginSettingsLocalDataSource {
     }
   }
 
+  Future<String> getReachabilityProbe() async {
+    try {
+      return preferences.getString(_reachabilityProbeKey) ?? '';
+    } catch (e) {
+      logger.e('Error loading reachability probe endpoint: $e');
+      return '';
+    }
+  }
+
+  Future<void> saveReachabilityProbe(String endpoint) async {
+    try {
+      final trimmed = endpoint.trim();
+      if (trimmed.isEmpty) {
+        await preferences.remove(_reachabilityProbeKey);
+      } else {
+        await preferences.setString(_reachabilityProbeKey, trimmed);
+      }
+      logger.i('Saved reachability probe endpoint: $trimmed');
+    } catch (e) {
+      logger.e('Error saving reachability probe endpoint: $e');
+      throw Exception('Failed to save reachability probe endpoint: $e');
+    }
+  }
+
   Future<bool> getAllowSelfSigned() async {
     try {
       final bool allowSelfSigned =
diff --git a/lib/features/login_settings/data/repositories/login_settings_repository.dart b/lib/features/login_settings/data/repositories/login_settings_repository.dart
index 46b2c5d..907a3d5 100644
--- a/lib/features/login_settings/data/repositories/login_settings_repository.dart
+++ b/lib/features/login_settings/data/repositories/login_settings_repository.dart
@@ -53,6 +53,22 @@ class LoginSettingsRepository {
     }
   }
 
+  Future<String> getReachabilityProbe() async {
+    try {
+      return await loginSettingsLocalDataSource.getReachabilityProbe();
+    } catch (e) {
+      return '';
+    }
+  }
+
+  Future<void> saveReachabilityProbe(String endpoint) async {
+    try {
+      await loginSettingsLocalDataSource.saveReachabilityProbe(endpoint);
+    } catch (e) {
+      rethrow;
+    }
+  }
+
   Future<bool> getAllowSelfSigned() async {
     try {
       return await loginSettingsLocalDataSource.getAllowSelfSigned();
diff --git a/lib/features/login_settings/presentation/pages/login_settings_page.dart b/lib/features/login_settings/presentation/pages/login_settings_page.dart
index 42c5541..7a4125e 100644
--- a/lib/features/login_settings/presentation/pages/login_settings_page.dart
+++ b/lib/features/login_settings/presentation/pages/login_settings_page.dart
@@ -119,6 +119,16 @@ class _LoginSettingsPage extends State<LoginSettingsPage> {
                         ),
                         _buildBasePathSection(context, state, localizations),
 
+                        _buildSectionTitle(
+                          context,
+                          localizations.reachabilityCheckTitle,
+                        ),
+                        _buildReachabilityProbeSection(
+                          context,
+                          state,
+                          localizations,
+                        ),
+
                         _buildSectionTitle(context, localizations.sslSettings),
                         _buildSSLSettingsSection(context, localizations, state),
 
@@ -266,6 +276,77 @@ class _LoginSettingsPage extends State<LoginSettingsPage> {
     );
   }
 
+  Widget _buildReachabilityProbeSection(
+    BuildContext context,
+    LoginSettingsState state,
+    AppLocalizations localizations,
+  ) {
+    return Card(
+      margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
+      elevation: 3,
+      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(8.0)),
+      child: Padding(
+        padding: const EdgeInsets.all(16),
+        child: Column(
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            Row(
+              children: [
+                Icon(
+                  Icons.network_check_rounded,
+                  size: 28,
+                  color: Theme.of(context).colorScheme.secondary,
+                ),
+                const SizedBox(width: 16),
+                Expanded(
+                  child: Column(
+                    crossAxisAlignment: CrossAxisAlignment.start,
+                    children: [
+                      Text(
+                        localizations.reachabilityCheckTitle,
+                        style: Theme.of(context).textTheme.titleMedium,
+                      ),
+                      const SizedBox(height: 4),
+                      Text(
+                        localizations.reachabilityCheckDescription,
+                        style: Theme.of(context).textTheme.bodySmall?.copyWith(
+                          color: Theme.of(context).colorScheme.onSurfaceVariant,
+                        ),
+                      ),
+                    ],
+                  ),
+                ),
+              ],
+            ),
+            const SizedBox(height: 24),
+            TextFormField(
+              initialValue: state.reachabilityProbe,
+              onChanged: (value) {
+                context.read<LoginSettingsBloc>().add(
+                  UpdateReachabilityProbe(value),
+                );
+              },
+              decoration: InputDecoration(
+                border: OutlineInputBorder(
+                  borderRadius: BorderRadius.circular(12.0),
+                ),
+                labelText: localizations.reachabilityCheckLabel,
+                hintText: localizations.reachabilityCheckHint,
+                prefixIcon: const Icon(Icons.wifi_tethering_rounded),
+                filled: true,
+                fillColor: Theme.of(context).colorScheme.surface,
+                contentPadding: const EdgeInsets.symmetric(
+                  horizontal: 16.0,
+                  vertical: 14.0,
+                ),
+              ),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+
   Widget _buildBasePathSection(
     BuildContext context,
     LoginSettingsState state,
diff --git a/lib/features/offline/presentation/pages/offline_home_page.dart b/lib/features/offline/presentation/pages/offline_home_page.dart
new file mode 100644
index 0000000..0d56d89
--- /dev/null
+++ b/lib/features/offline/presentation/pages/offline_home_page.dart
@@ -0,0 +1,200 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+
+import 'package:calibre_web_companion/l10n/app_localizations.dart';
+import 'package:calibre_web_companion/features/offline/cubit/connectivity_cubit.dart';
+import 'package:calibre_web_companion/features/offline/presentation/pages/offline_library_page.dart';
+import 'package:calibre_web_companion/features/login_settings/presentation/pages/login_settings_page.dart';
+import 'package:calibre_web_companion/features/login_settings/presentation/pages/connection_diagnostics_page.dart';
+import 'package:calibre_web_companion/features/login/presentation/pages/login_page.dart';
+
+class OfflineHomePage extends StatefulWidget {
+  const OfflineHomePage({super.key});
+
+  @override
+  State<OfflineHomePage> createState() => _OfflineHomePageState();
+}
+
+class _OfflineHomePageState extends State<OfflineHomePage> {
+  int _index = 0;
+
+  @override
+  Widget build(BuildContext context) {
+    final localizations = AppLocalizations.of(context)!;
+
+    return Scaffold(
+      appBar: AppBar(
+        title: Text(localizations.offline),
+        actions: [
+          IconButton(
+            icon: const Icon(Icons.refresh_rounded),
+            tooltip: localizations.retry,
+            onPressed: () => context.read<ConnectivityCubit>().recheck(),
+          ),
+        ],
+      ),
+      body: IndexedStack(
+        index: _index,
+        children: [
+          _buildLibraryTab(context, localizations),
+          const _OfflineMenu(),
+        ],
+      ),
+      bottomNavigationBar: NavigationBar(
+        selectedIndex: _index,
+        labelBehavior: NavigationDestinationLabelBehavior.alwaysShow,
+        onDestinationSelected: (i) => setState(() => _index = i),
+        destinations: [
+          NavigationDestination(
+            icon: const Icon(Icons.book_rounded),
+            label: localizations.books,
+          ),
+          NavigationDestination(
+            icon: const Icon(Icons.settings_rounded),
+            label: localizations.settings,
+          ),
+        ],
+      ),
+    );
+  }
+
+  Widget _buildLibraryTab(
+    BuildContext context,
+    AppLocalizations localizations,
+  ) {
+    final theme = Theme.of(context);
+    return Column(
+      children: [
+        Container(
+          width: double.infinity,
+          color: theme.colorScheme.secondaryContainer,
+          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
+          child: Row(
+            children: [
+              Icon(
+                Icons.cloud_off_rounded,
+                size: 20,
+                color: theme.colorScheme.onSecondaryContainer,
+              ),
+              const SizedBox(width: 10),
+              Expanded(
+                child: Text(
+                  localizations.offlineBannerMessage,
+                  style: theme.textTheme.bodyMedium?.copyWith(
+                    color: theme.colorScheme.onSecondaryContainer,
+                  ),
+                ),
+              ),
+            ],
+          ),
+        ),
+        const Expanded(child: OfflineLibraryPage()),
+      ],
+    );
+  }
+}
+
+class _OfflineMenu extends StatelessWidget {
+  const _OfflineMenu();
+
+  @override
+  Widget build(BuildContext context) {
+    final localizations = AppLocalizations.of(context)!;
+
+    return ListView(
+      padding: const EdgeInsets.symmetric(vertical: 8),
+      children: [
+        _MenuCard(
+          icon: Icons.refresh_rounded,
+          title: localizations.tryAgain,
+          onTap: () => context.read<ConnectivityCubit>().recheck(),
+        ),
+        _MenuCard(
+          icon: Icons.link_rounded,
+          title: localizations.connectionSettings,
+          onTap:
+              () => Navigator.of(context).push(
+                MaterialPageRoute(builder: (_) => const LoginSettingsPage()),
+              ),
+        ),
+        _MenuCard(
+          icon: Icons.troubleshoot_rounded,
+          title: localizations.connectionDiagnostics,
+          subtitle: localizations.connectionDiagnosticsSubtitle,
+          onTap:
+              () => Navigator.of(context).push(
+                MaterialPageRoute(
+                  builder: (_) => const ConnectionDiagnosticsPage(),
+                ),
+              ),
+        ),
+        _MenuCard(
+          icon: Icons.manage_accounts_rounded,
+          title: localizations.accounts,
+          onTap:
+              () => Navigator.of(
+                context,
+              ).push(MaterialPageRoute(builder: (_) => const LoginPage())),
+        ),
+      ],
+    );
+  }
+}
+
+class _MenuCard extends StatelessWidget {
+  final IconData icon;
+  final String title;
+  final String? subtitle;
+  final VoidCallback onTap;
+
+  const _MenuCard({
+    required this.icon,
+    required this.title,
+    required this.onTap,
+    this.subtitle,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    return Card(
+      margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 6),
+      elevation: 3,
+      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(8.0)),
+      clipBehavior: Clip.antiAlias,
+      child: InkWell(
+        onTap: onTap,
+        child: Padding(
+          padding: const EdgeInsets.all(16),
+          child: Row(
+            children: [
+              Icon(icon, size: 28, color: theme.colorScheme.secondary),
+              const SizedBox(width: 16),
+              Expanded(
+                child: Column(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  children: [
+                    Text(title, style: theme.textTheme.titleMedium),
+                    if (subtitle != null) ...[
+                      const SizedBox(height: 4),
+                      Text(
+                        subtitle!,
+                        style: theme.textTheme.bodySmall?.copyWith(
+                          color: theme.colorScheme.onSurfaceVariant,
+                        ),
+                      ),
+                    ],
+                  ],
+                ),
+              ),
+              Icon(
+                Icons.chevron_right_rounded,
+                color: theme.colorScheme.onSurfaceVariant,
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}
diff --git a/lib/l10n/app_en.arb b/lib/l10n/app_en.arb
index 75df2fe..4dfa3a6 100644
--- a/lib/l10n/app_en.arb
+++ b/lib/l10n/app_en.arb
@@ -325,6 +325,10 @@
   "basePathLabel": "Base Path",
   "basePathHint": "e.g., /opds or /calibre",
   "basePathDescription": "Define a custom base path for API requests",
+  "reachabilityCheckTitle": "Reachability Check",
+  "reachabilityCheckLabel": "Probe endpoint",
+  "reachabilityCheckHint": "e.g., /ajax/listbooks?limit=1",
+  "reachabilityCheckDescription": "The endpoint used to test whether the server is online. Leave empty to use the default for your server type.",
   "bookCover": "Book cover",
   "currentCover": "Current cover",
   "newCover": "New cover",