diff --git a/CHANGELOG.md b/CHANGELOG.md
index ee17d2be..e3fb7c7d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -45,6 +45,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- **Frontend date/time unit tests no longer fail outside UTC / en-US.** Three tests encoded the machine timezone or locale into their expectations (`dateTimeUtils.isSame`, `RecordingUtils.toDateString`, `SeriesModalUtils.getEpisodeAirdate`), so the suite failed on boxes east of UTC or non-US locales. Fixtures now use local calendar datetimes and locale-computed expectations so the suite passes in every environment. — Thanks [@nagelm](https://github.com/nagelm)
+- **API error toasts no longer dump raw HTML error pages.** Failed responses that return Django or nginx HTML (for example 500/502/504 when the backend is down) were interpolated into the toast body as markup. Errors are now formatted for display: JSON bodies prefer `detail` / `error` / field messages, HTML and empty bodies collapse to a short status line, and long plain-text bodies are truncated. — Thanks [@nagelm](https://github.com/nagelm)
 - **Swagger/OpenAPI schema generation no longer fails under concurrent gevent requests.** Concurrent hits to `/api/schema/` (for example Swagger UI loading) could race on DRF's shared `AutoSchema` state and raise `AssertionError: Schema generation REQUIRES a view instance`, leaving Swagger empty. Cold builds could also hang the gevent uWSGI worker. Schema introspection now runs in a real OS thread, builds are single-flight per process, and the result is cached in Django's cache (Redis) so all workers share it.
 - **`/proxy/ts/change_stream` now persists `stream_id` and waits for the real switch outcome in multi-worker deployments.** When the request landed on a worker that didn't own the channel, the owning worker's `STREAM_SWITCH` pubsub handler performed the switch but wrote only `url`/`user_agent` back to the channel's Redis metadata, so `GET /proxy/ts/status` kept reporting the old `stream_id` indefinitely; the handler now persists the full switch metadata (`stream_id`, `m3u_profile`, stream name) via the same `_update_channel_metadata()` helper the direct owner path uses. `stream_name` from the initial `get_stream_info_for_switch()` lookup is now forwarded through the pubsub payload (and from `change_stream` / `next_stream` on the direct owner path) so the owner no longer re-queries the database when writing metadata. The endpoint also no longer returns an optimistic 200 on the non-owner path: the requesting worker waits (up to 15s) for the owner to confirm via the `switch_status` Redis key and answers 502 if the owner reports failure or 504 if no confirmation arrives (e.g. owner worker gone); `next_stream` gets the same treatment. Requesting a switch to the URL the channel is already playing is now treated as success (with a metadata refresh) instead of a silent no-op, and the `switch_status` key now expires (60s TTL) instead of persisting forever. (Fixes #1412)
 - **XC live streams, `/panel_api.php`, and `/xmltv.php` no longer crash when a visible channel has no channel number.** Since `channel_number` became nullable, auto-sync and compact numbering can leave a channel with `effective_channel_number=None` while it remains visible in output (`hidden_from_output=False`). The XC live-stream number map skipped those rows but still tried to emit them, causing `KeyError` on `get_live_streams` and a 500 on `/panel_api.php` (`xc_get_info`). Authenticated XMLTV export (`/xmltv.php`, profile EPG with a logged-in user) had the same gap and could fail chunk-cache rebuilds with `KeyError` on `channel_num_map[channel.id]`. Null-number channels are now deferred into the existing collision-free integer assignment pass (same second loop as fractional numbers) and receive the next available integer; `_xc_channel_entry` also falls back to `channel.id` if a row is still unmapped. HDHR lineup behaviour is unchanged (null-number channels remain omitted there).
diff --git a/frontend/src/__tests__/formatApiError.test.js b/frontend/src/__tests__/formatApiError.test.js
new file mode 100644
index 00000000..d1e92ef9
--- /dev/null
+++ b/frontend/src/__tests__/formatApiError.test.js
@@ -0,0 +1,196 @@
+import { describe, expect, it, vi } from 'vitest';
+
+import { formatApiError } from '../utils';
+
+const djangoHtml500 =
+  '<!doctype html> <html lang="en"> <head> <title>Server Error (500)</title> </head> <body> <h1>Server Error (500)</h1><p> </p> </body> </html>';
+
+const fakeResponse = (statusText, contentType) => ({
+  statusText,
+  headers: { get: (name) => (name === 'content-type' ? contentType : null) },
+});
+
+describe('formatApiError', () => {
+  it('replaces a Django HTML 500 body with the response status line', () => {
+    const msg = formatApiError({
+      status: 500,
+      body: djangoHtml500,
+      response: fakeResponse('Internal Server Error', 'text/html'),
+    });
+    expect(msg).toBe('500 - Internal Server Error');
+    expect(msg).not.toContain('<');
+  });
+
+  it('uses the reason phrase for nginx gateway HTML pages', () => {
+    expect(
+      formatApiError({
+        status: 504,
+        body: '<html><body><h1>504 Gateway Time-out</h1></body></html>',
+        response: fakeResponse('Gateway Time-out', 'text/html'),
+      })
+    ).toBe('504 - Gateway Time-out');
+    expect(
+      formatApiError({
+        status: 502,
+        body: '<html></html>',
+        response: fakeResponse('Bad Gateway', 'text/html'),
+      })
+    ).toBe('502 - Bad Gateway');
+  });
+
+  it('trusts the declared content type over body sniffing', () => {
+    const msg = formatApiError({
+      status: 503,
+      body: 'upstream connect error <html>...</html>',
+      response: fakeResponse('Service Unavailable', 'text/html; charset=utf-8'),
+    });
+    expect(msg).toBe('503 - Service Unavailable');
+  });
+
+  it('sniffs markup when no content type is available', () => {
+    expect(formatApiError({ status: 500, body: djangoHtml500 })).toBe(
+      '500 - Internal Server Error'
+    );
+  });
+
+  it('does not sniff markup when content type is explicitly non-html', () => {
+    expect(
+      formatApiError({
+        status: 400,
+        body: '<name> is invalid',
+        response: fakeResponse('Bad Request', 'text/plain'),
+      })
+    ).toBe('400 - <name> is invalid');
+  });
+
+  it('uses a status label when the reason phrase is absent (HTTP/2)', () => {
+    expect(
+      formatApiError({
+        status: 502,
+        body: '<html></html>',
+        response: fakeResponse('', 'text/html'),
+      })
+    ).toBe('502 - Bad Gateway');
+  });
+
+  it('preserves the suppressed HTML body via console.debug', () => {
+    const spy = vi.spyOn(console, 'debug').mockImplementation(() => {});
+    formatApiError({
+      status: 500,
+      body: djangoHtml500,
+      response: fakeResponse('Internal Server Error', 'text/html'),
+    });
+    expect(spy).toHaveBeenCalledWith(
+      'API error 500 response body:',
+      djangoHtml500
+    );
+    spy.mockRestore();
+  });
+
+  it('extracts detail from DRF-style JSON bodies', () => {
+    expect(
+      formatApiError({
+        status: 401,
+        body: {
+          detail: 'No active account found with the given credentials',
+        },
+      })
+    ).toBe('No active account found with the given credentials');
+  });
+
+  it('extracts error from custom API JSON bodies', () => {
+    expect(
+      formatApiError({ status: 500, body: { error: 'Redis not available' } })
+    ).toBe('Redis not available');
+  });
+
+  it('extracts non_field_errors when detail/error are absent', () => {
+    expect(
+      formatApiError({
+        status: 400,
+        body: {
+          non_field_errors: ['Unable to log in with provided credentials.'],
+        },
+      })
+    ).toBe('Unable to log in with provided credentials.');
+  });
+
+  it('prefers detail over other JSON keys', () => {
+    expect(
+      formatApiError({
+        status: 400,
+        body: {
+          detail: 'Primary message',
+          error: 'Secondary',
+          name: ['ignored when detail is present'],
+        },
+      })
+    ).toBe('Primary message');
+  });
+
+  it('joins DRF field validation errors', () => {
+    expect(
+      formatApiError({
+        status: 400,
+        body: { name: ['This field is required.'] },
+      })
+    ).toBe('name: This field is required.');
+    expect(
+      formatApiError({
+        status: 400,
+        body: {
+          name: ['This field is required.'],
+          url: ['Enter a valid URL.'],
+        },
+      })
+    ).toBe('name: This field is required.; url: Enter a valid URL.');
+  });
+
+  it('passes through short plain-text bodies with the status', () => {
+    expect(
+      formatApiError({
+        status: 403,
+        body: 'Forbidden by policy',
+        response: fakeResponse('Forbidden', 'text/plain'),
+      })
+    ).toBe('403 - Forbidden by policy');
+  });
+
+  it('truncates long plain-text bodies', () => {
+    const long = 'x'.repeat(500);
+    const msg = formatApiError({
+      status: 500,
+      body: long,
+      response: fakeResponse('Internal Server Error', 'text/plain'),
+    });
+    expect(msg.length).toBeLessThanOrEqual(210);
+    expect(msg.endsWith('...')).toBe(true);
+  });
+
+  it('uses the status line when the body is empty', () => {
+    expect(
+      formatApiError({
+        status: 503,
+        body: '',
+        response: fakeResponse('Service Unavailable', ''),
+      })
+    ).toBe('503 - Service Unavailable');
+  });
+
+  it('handles non-standard statuses via the server-provided reason phrase', () => {
+    expect(
+      formatApiError({
+        status: 599,
+        body: '<html></html>',
+        response: fakeResponse('Network Connect Timeout Error', 'text/html'),
+      })
+    ).toBe('599 - Network Connect Timeout Error');
+  });
+
+  it('uses error.message for non-HTTP errors (fetch/network failures)', () => {
+    expect(formatApiError(new TypeError('Failed to fetch'))).toBe(
+      'Failed to fetch'
+    );
+    expect(formatApiError({})).toBe('Unknown error');
+  });
+});
diff --git a/frontend/src/api.js b/frontend/src/api.js
index 50db0165..3a745896 100644
--- a/frontend/src/api.js
+++ b/frontend/src/api.js
@@ -15,7 +15,7 @@ import useChannelsTableStore from './store/channelsTable';
 import useStreamsTableStore from './store/streamsTable';
 import useUsersStore from './store/users';
 import useConnectStore from './store/connect';
-import Limiter from './utils';
+import Limiter, { formatApiError } from './utils';
 
 // If needed, you can set a base host or keep it empty if relative requests
 const host = import.meta.env.DEV
@@ -23,22 +23,7 @@ const host = import.meta.env.DEV
   : '';
 
 const errorNotification = (message, error) => {
-  let errorMessage = '';
-
-  if (error.status) {
-    try {
-      // Try to format the error body if it's an object
-      if (typeof error.body === 'object') {
-        errorMessage = JSON.stringify(error.body, null, 2);
-      } else {
-        errorMessage = `${error.status} - ${error.body}`;
-      }
-    } catch (e) {
-      errorMessage = `${error.status} - ${String(error.body)}`;
-    }
-  } else {
-    errorMessage = error.message || 'Unknown error';
-  }
+  const errorMessage = formatApiError(error);
 
   notifications.show({
     title: 'Error',
diff --git a/frontend/src/utils.js b/frontend/src/utils.js
index 27abf86c..c14863cd 100644
--- a/frontend/src/utils.js
+++ b/frontend/src/utils.js
@@ -68,6 +68,115 @@ export function useDebounce(value, delay = 500, callback = null) {
   return debouncedValue;
 }
 
+// Format a failed API response for toast display.
+const ERROR_BODY_MAX_CHARS = 200;
+
+const STATUS_LABELS = {
+  400: 'Bad Request',
+  401: 'Unauthorized',
+  403: 'Forbidden',
+  404: 'Not Found',
+  405: 'Method Not Allowed',
+  408: 'Request Timeout',
+  409: 'Conflict',
+  413: 'Payload Too Large',
+  429: 'Too Many Requests',
+  500: 'Internal Server Error',
+  502: 'Bad Gateway',
+  503: 'Service Unavailable',
+  504: 'Gateway Timeout',
+};
+
+const formatErrorValue = (value) => {
+  if (value == null) return '';
+  if (Array.isArray(value)) {
+    return value.map(formatErrorValue).filter(Boolean).join('; ');
+  }
+  if (typeof value === 'object') {
+    try {
+      return JSON.stringify(value);
+    } catch {
+      return '';
+    }
+  }
+  return String(value);
+};
+
+const formatJsonErrorBody = (body) => {
+  if (Array.isArray(body)) {
+    return formatErrorValue(body) || null;
+  }
+  if (!body || typeof body !== 'object') {
+    return null;
+  }
+
+  for (const key of ['detail', 'error', 'non_field_errors']) {
+    if (body[key] != null && body[key] !== '') {
+      const msg = formatErrorValue(body[key]);
+      if (msg) return msg;
+    }
+  }
+
+  const fieldParts = Object.entries(body)
+    .map(([key, value]) => {
+      const msg = formatErrorValue(value);
+      return msg ? `${key}: ${msg}` : null;
+    })
+    .filter(Boolean);
+
+  if (fieldParts.length) {
+    return fieldParts.join('; ');
+  }
+
+  try {
+    return JSON.stringify(body, null, 2);
+  } catch {
+    return null;
+  }
+};
+
+const formatStatusLine = (status, response) => {
+  const reason = response?.statusText?.trim();
+  const label = reason || STATUS_LABELS[status] || 'Request failed';
+  return `${status} - ${label}`;
+};
+
+export const formatApiError = (error) => {
+  if (!error || !error.status) {
+    return (error && error.message) || 'Unknown error';
+  }
+
+  const { status, body, response } = error;
+
+  if (body && typeof body === 'object') {
+    const formatted = formatJsonErrorBody(body);
+    if (formatted) return formatted;
+  }
+
+  const text =
+    typeof body === 'string' ? body.trim() : body == null ? '' : String(body);
+
+  // Sniff leading '<' only when Content-Type is missing.
+  const contentType = (
+    response?.headers?.get?.('content-type') || ''
+  ).toLowerCase();
+  const isMarkup =
+    contentType.includes('html') ||
+    contentType.includes('xml') ||
+    (!contentType && text.startsWith('<'));
+
+  if (!text || isMarkup) {
+    if (text) {
+      console.debug(`API error ${status} response body:`, text);
+    }
+    return formatStatusLine(status, response);
+  }
+
+  return text.length > ERROR_BODY_MAX_CHARS
+    ? `${status} - ${text.slice(0, ERROR_BODY_MAX_CHARS)}...`
+    : `${status} - ${text}`;
+};
+
 export function sleep(ms) {
   return new Promise((resolve) => {
     setTimeout(resolve, ms);
diff --git a/frontend/src/utils/__tests__/dateTimeUtils.test.js b/frontend/src/utils/__tests__/dateTimeUtils.test.js
index 3bc642af..0e841074 100644
--- a/frontend/src/utils/__tests__/dateTimeUtils.test.js
+++ b/frontend/src/utils/__tests__/dateTimeUtils.test.js
@@ -132,14 +132,14 @@ describe('dateTimeUtils', () => {
 
   describe('isSame', () => {
     it('should return true when dates are same day', () => {
-      const date1 = '2024-01-15T10:00:00Z';
-      const date2 = '2024-01-15T11:00:00Z';
+      const date1 = '2024-01-15 10:00:00';
+      const date2 = '2024-01-15 11:00:00';
       expect(dateTimeUtils.isSame(date1, date2)).toBe(true);
     });
 
     it('should return false when dates are different days', () => {
-      const date1 = '2024-01-15T10:00:00Z';
-      const date2 = '2024-01-16T10:00:00Z';
+      const date1 = '2024-01-15 10:00:00';
+      const date2 = '2024-01-16 10:00:00';
       expect(dateTimeUtils.isSame(date1, date2)).toBe(false);
     });
 
diff --git a/frontend/src/utils/components/__tests__/SeriesModalUtils.test.js b/frontend/src/utils/components/__tests__/SeriesModalUtils.test.js
index d986cfcc..5f4f4490 100644
--- a/frontend/src/utils/components/__tests__/SeriesModalUtils.test.js
+++ b/frontend/src/utils/components/__tests__/SeriesModalUtils.test.js
@@ -353,7 +353,7 @@ describe('SeriesModalUtils', () => {
     it('should format valid air date', () => {
       const episode = { air_date: '2024-01-15' };
       const formatted = getEpisodeAirdate(episode);
-      expect(formatted).toMatch(/1\/1[4|5]\/2024/);
+      expect(formatted).toBe(new Date('2024-01-15').toLocaleDateString());
     });
 
     it('should return N/A for missing air date', () => {
diff --git a/frontend/src/utils/forms/__tests__/RecordingUtils.test.js b/frontend/src/utils/forms/__tests__/RecordingUtils.test.js
index 6e3ae901..db74a1f9 100644
--- a/frontend/src/utils/forms/__tests__/RecordingUtils.test.js
+++ b/frontend/src/utils/forms/__tests__/RecordingUtils.test.js
@@ -111,7 +111,7 @@ describe('RecordingUtils', () => {
 
   describe('toDateString', () => {
     it('formats a Date to YYYY-MM-DD', () => {
-      const d = new Date('2024-06-15T12:00:00Z');
+      const d = new Date(2024, 5, 15, 12, 0, 0);
       const result = toDateString(d);
       expect(result).toBe('2024-06-15');
     });