diff --git a/frontend/lib/devices/device_actions.dart b/frontend/lib/devices/device_actions.dart
index 8f30de9..f651b8b 100644
--- a/frontend/lib/devices/device_actions.dart
+++ b/frontend/lib/devices/device_actions.dart
@@ -42,7 +42,10 @@ Future<void> confirmForgetDevice(
     onRefresh();
   } catch (e) {
     if (!context.mounted) return;
-    UISnackbars.showError(context, 'Failed to forget device: $e');
+    UISnackbars.showError(
+      context,
+      'Failed to forget device. ${dioErrorToUserMessage(e)}',
+    );
   }
 }
 
@@ -157,7 +160,10 @@ Future<void> showEditDeviceDialog(
     onRefresh();
   } catch (e) {
     if (!context.mounted) return;
-    UISnackbars.showError(context, 'Failed to update device: $e');
+    UISnackbars.showError(
+      context,
+      'Failed to update device. ${dioErrorToUserMessage(e)}',
+    );
   }
 }
 
@@ -260,6 +266,9 @@ Future<void> showRegisterDeviceDialog(
     onRefresh();
   } catch (e) {
     if (!context.mounted) return;
-    UISnackbars.showError(context, 'Failed to register device: $e');
+    UISnackbars.showError(
+      context,
+      'Failed to register device. ${dioErrorToUserMessage(e)}',
+    );
   }
 }
diff --git a/frontend/lib/devices/device_list.dart b/frontend/lib/devices/device_list.dart
index e83d877..2fc46d4 100644
--- a/frontend/lib/devices/device_list.dart
+++ b/frontend/lib/devices/device_list.dart
@@ -102,7 +102,7 @@ class _DeviceListState extends State<DeviceList> with RouteAware {
     } catch (e) {
       if (!mounted) return;
       setState(() {
-        _error = e.toString();
+        _error = dioErrorToUserMessage(e);
         _isLoading = false;
       });
     }
@@ -235,7 +235,12 @@ class _DeviceListState extends State<DeviceList> with RouteAware {
       return const Center(child: CircularProgressIndicator());
     }
     if (_error != null) {
-      return Center(child: Text('Error: $_error'));
+      return Center(
+        child: Text(
+          'Error: $_error',
+          style: TextStyle(color: Theme.of(context).colorScheme.error),
+        ),
+      );
     }
     if (_devices.isEmpty) {
       final theme = Theme.of(context);
diff --git a/frontend/lib/home/notifications_list.dart b/frontend/lib/home/notifications_list.dart
index 6562ff5..9fa215f 100644
--- a/frontend/lib/home/notifications_list.dart
+++ b/frontend/lib/home/notifications_list.dart
@@ -44,6 +44,7 @@ class _NotificationsListState extends State<NotificationsList> with RouteAware {
   List<oott_model.Notification> _items = [];
   bool _isLoading = false;
   bool _hasNextPage = false;
+  String? _error;
 
   @override
   void initState() {
@@ -78,10 +79,16 @@ class _NotificationsListState extends State<NotificationsList> with RouteAware {
 
   Future<void> _fetchPage(int page) async {
     if (_isLoading) return;
-    setState(() => _isLoading = true);
+    setState(() {
+      _isLoading = true;
+      _error = null;
+    });
     try {
-      final results = await BackendAPI.instance
-          .listNotifications(_filter.isNew, page * _pageSize, limit: _pageSize + 1);
+      final results = await BackendAPI.instance.listNotifications(
+        _filter.isNew,
+        page * _pageSize,
+        limit: _pageSize + 1,
+      );
       if (!mounted) return;
       setState(() {
         _currentPage = page;
@@ -89,9 +96,12 @@ class _NotificationsListState extends State<NotificationsList> with RouteAware {
         _items = _hasNextPage ? results.take(_pageSize).toList() : results;
         _isLoading = false;
       });
-    } catch (_) {
+    } catch (e) {
       if (!mounted) return;
-      setState(() => _isLoading = false);
+      setState(() {
+        _error = dioErrorToUserMessage(e);
+        _isLoading = false;
+      });
     }
   }
 
@@ -205,6 +215,18 @@ class _NotificationsListState extends State<NotificationsList> with RouteAware {
         ),
       ];
     }
+    if (_error != null) {
+      return [
+        SliverFillRemaining(
+          child: Center(
+            child: Text(
+              'Error: $_error',
+              style: TextStyle(color: Theme.of(context).colorScheme.error),
+            ),
+          ),
+        ),
+      ];
+    }
     if (_items.isEmpty) {
       return [
         SliverToBoxAdapter(
diff --git a/frontend/lib/utils/oott_api.dart b/frontend/lib/utils/oott_api.dart
index 6c65ced..c116cb8 100644
--- a/frontend/lib/utils/oott_api.dart
+++ b/frontend/lib/utils/oott_api.dart
@@ -12,6 +12,44 @@ import '../model/device_summary.dart';
 import '../model/device_type.dart';
 import '../model/notification.dart';
 
+const _connectTimeout = Duration(seconds: 5);
+const _receiveTimeout = Duration(seconds: 15);
+const _sendTimeout = Duration(seconds: 15);
+
+String dioErrorToUserMessage(Object error) {
+  if (error is! DioException) {
+    debugPrint('Non-Dio error from backend call: $error');
+    return 'Unexpected error.';
+  }
+  switch (error.type) {
+    case DioExceptionType.connectionTimeout:
+    case DioExceptionType.sendTimeout:
+    case DioExceptionType.receiveTimeout:
+      return 'Backend did not respond in time.';
+    case DioExceptionType.connectionError:
+      return 'Cannot reach backend. Check the base URL and your network.';
+    case DioExceptionType.badCertificate:
+      return 'Backend TLS certificate could not be verified.';
+    case DioExceptionType.cancel:
+      return 'Request canceled.';
+    case DioExceptionType.badResponse:
+      final status = error.response?.statusCode;
+      if (status == 401 || status == 403) {
+        return 'Authentication failed. Check your API key in Settings.';
+      }
+      if (status == 404) {
+        return 'Not found.';
+      }
+      if (status != null && status >= 500 && status < 600) {
+        return 'Backend error (status $status). Please try again.';
+      }
+      return 'Unexpected response from backend (status ${status ?? 'unknown'}).';
+    case DioExceptionType.unknown:
+      debugPrint('Unknown Dio error: ${error.message}');
+      return 'Unexpected error contacting backend.';
+  }
+}
+
 class BackendAPI {
   static final BackendAPI _instance = BackendAPI._internal();
   static const _pageSize = 5;
@@ -24,11 +62,14 @@ class BackendAPI {
     _apiKey = XOR().xorDecode(PrefUtil.getValue("api_key", "") as String);
 
     debugPrint('Base URL: $_baseUrl');
-    debugPrint('API KEY: $_apiKey');
+    debugPrint('API KEY: ${_apiKey.isEmpty ? "<empty>" : "<set>"}');
 
     _dio = Dio(
       BaseOptions(
         baseUrl: _baseUrl,
+        connectTimeout: _connectTimeout,
+        receiveTimeout: _receiveTimeout,
+        sendTimeout: _sendTimeout,
         headers: {
           HttpHeaders.contentTypeHeader: 'application/json',
           HttpHeaders.authorizationHeader: 'Bearer $_apiKey',
@@ -39,10 +80,13 @@ class BackendAPI {
 
   // Returns null if the test was successful, and a String with a message about the issue if not
   static Future<String?> test(String baseUrl, String apiKey) async {
-    debugPrint('About to test API with baseUrl=$baseUrl and apiKey=$apiKey');
+    debugPrint('About to test API with baseUrl=$baseUrl');
     Dio dio = Dio(
       BaseOptions(
         baseUrl: baseUrl,
+        connectTimeout: _connectTimeout,
+        receiveTimeout: _receiveTimeout,
+        sendTimeout: _sendTimeout,
         headers: {
           HttpHeaders.contentTypeHeader: 'application/json',
           HttpHeaders.authorizationHeader: 'Bearer $apiKey',
@@ -55,17 +99,8 @@ class BackendAPI {
       return response.toString().contains('OOTT_API_OK')
           ? null
           : "URL successfully called but didn't return the expected value. Check your URL and make sure it points to your OOTT backend base URL.";
-    } on DioException catch (e) {
-      if (e.response != null) {
-        if (e.response!.statusCode == 401) {
-          return "Authorization failed, check your API Key.";
-        } else {
-          return "Error querying the given URL (${e.response!.statusCode} - ${e.message ?? 'N/A'})";
-        }
-      } else {
-        // Response was null, something happened while sending the message
-        return "Error sending message to provided URL (${e.message ?? 'no message'})";
-      }
+    } catch (e) {
+      return dioErrorToUserMessage(e);
     }
   }
 
diff --git a/frontend/lib/widgets/scanners_status_card.dart b/frontend/lib/widgets/scanners_status_card.dart
index c2f63a4..94c8819 100644
--- a/frontend/lib/widgets/scanners_status_card.dart
+++ b/frontend/lib/widgets/scanners_status_card.dart
@@ -48,7 +48,7 @@ class _ScannersStatusCardState extends State<ScannersStatusCard> {
     try {
       arp = await BackendAPI.instance.getArpScannerStatus();
     } catch (e) {
-      arpError = e.toString();
+      arpError = dioErrorToUserMessage(e);
     }
 
     MdnsScannerStatus? mdns;
@@ -56,7 +56,7 @@ class _ScannersStatusCardState extends State<ScannersStatusCard> {
     try {
       mdns = await BackendAPI.instance.getMdnsScannerStatus();
     } catch (e) {
-      mdnsError = e.toString();
+      mdnsError = dioErrorToUserMessage(e);
     }
 
     if (!mounted) return;
@@ -99,9 +99,9 @@ class _ScannersStatusCardState extends State<ScannersStatusCard> {
             children: [
               Text('Status', style: Theme.of(context).textTheme.titleMedium),
               const SizedBox(height: 12),
-              _scannerRow(context, arpColor, 'ARP', arpText),
+              _scannerRow(context, arpColor, 'ARP', arpText, _arpError),
               const SizedBox(height: 8),
-              _scannerRow(context, mdnsColor, 'mDNS', mdnsText),
+              _scannerRow(context, mdnsColor, 'mDNS', mdnsText, _mdnsError),
             ],
           ),
         ),
@@ -114,10 +114,15 @@ class _ScannersStatusCardState extends State<ScannersStatusCard> {
     Color color,
     String name,
     String statusText,
+    String? errorMessage,
   ) {
+    Widget dot = Icon(Icons.circle, color: color, size: 12);
+    if (errorMessage != null) {
+      dot = Tooltip(message: errorMessage, child: dot);
+    }
     return Row(
       children: [
-        Icon(Icons.circle, color: color, size: 12),
+        dot,
         const SizedBox(width: 10),
         Expanded(
           child: Text(name, style: Theme.of(context).textTheme.bodyMedium),