diff --git a/packages/sync-providers/src/file-based/dropbox/dropbox-api.ts b/packages/sync-providers/src/file-based/dropbox/dropbox-api.ts
index 2bde2b5779..57715e8ec0 100644
--- a/packages/sync-providers/src/file-based/dropbox/dropbox-api.ts
+++ b/packages/sync-providers/src/file-based/dropbox/dropbox-api.ts
@@ -528,10 +528,7 @@ export class DropboxApi {
 
         if (!response.ok) {
           const bodyStr = await response.text();
-          throw new HttpNotOkAPIError(
-            new Response(bodyStr, { status: response.status }),
-            bodyStr,
-          );
+          throw new HttpNotOkAPIError(response, bodyStr);
         }
 
         data = (await response.json()) as TokenResponse;
diff --git a/packages/sync-providers/tests/file-based/dropbox/dropbox-api.spec.ts b/packages/sync-providers/tests/file-based/dropbox/dropbox-api.spec.ts
index 82243aa5bb..5f41b23101 100644
--- a/packages/sync-providers/tests/file-based/dropbox/dropbox-api.spec.ts
+++ b/packages/sync-providers/tests/file-based/dropbox/dropbox-api.spec.ts
@@ -1,6 +1,7 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import {
   AuthFailSPError,
+  HttpNotOkAPIError,
   RemoteFileNotFoundAPIError,
   TooManyRequestsAPIError,
   UploadRevToMatchMismatchAPIError,
@@ -571,6 +572,37 @@ describe('DropboxApi', () => {
       expect(body).toContain('grant_type=authorization_code');
     });
 
+    it('preserves response metadata when the token exchange fails', async () => {
+      const headers = new Headers();
+      headers.set('X-Dropbox-Request-Id', 'dbx-request-123');
+      const response = new Response('gateway timeout', {
+        status: 504,
+        statusText: 'Gateway Timeout',
+        headers,
+      });
+      fetchSpy.mockResolvedValue(response);
+
+      let thrown: HttpNotOkAPIError | undefined;
+      try {
+        await dropboxApi.getTokensFromAuthCode(
+          'test-auth-code',
+          'test-code-verifier',
+          null,
+        );
+      } catch (error) {
+        if (error instanceof HttpNotOkAPIError) {
+          thrown = error;
+        }
+      }
+
+      expect(thrown).toBeDefined();
+      expect(thrown?.response).toBe(response);
+      expect(thrown?.message).toBe('HTTP 504 Gateway Timeout');
+      expect(thrown?.response.headers.get('X-Dropbox-Request-Id')).toBe(
+        'dbx-request-123',
+      );
+    });
+
     it('should throw error for invalid token response', async () => {
       fetchSpy.mockResolvedValue({
         ok: true,
diff --git a/src/app/imex/sync/sync-wrapper.service.spec.ts b/src/app/imex/sync/sync-wrapper.service.spec.ts
index 823757b1b8..fac9800aee 100644
--- a/src/app/imex/sync/sync-wrapper.service.spec.ts
+++ b/src/app/imex/sync/sync-wrapper.service.spec.ts
@@ -40,10 +40,14 @@ import {
   EncryptNoPasswordError,
   ForceUploadFailedError,
   ForceUploadPendingOpsError,
+  HttpNotOkAPIError,
   IncompleteRemoteOperationsError,
 } from '../../op-log/core/errors/sync-errors';
 import { DialogEnterEncryptionPasswordComponent } from './dialog-enter-encryption-password/dialog-enter-encryption-password.component';
 import { MAX_LWW_REUPLOAD_RETRIES } from '../../op-log/core/operation-log.const';
+import type { SyncProviderBase } from '../../op-log/sync-providers/provider.interface';
+import type { MatDialogRef } from '@angular/material/dialog';
+import { DialogGetAndEnterAuthCodeComponent } from './dialog-get-and-enter-auth-code/dialog-get-and-enter-auth-code.component';
 
 describe('SyncWrapperService', () => {
   let service: SyncWrapperService;
@@ -426,6 +430,79 @@ describe('SyncWrapperService', () => {
     });
   });
 
+  describe('configuredAuthForSyncProviderIfNecessary()', () => {
+    it('shows a temporary service error with the Dropbox request ID for HTTP 504', async () => {
+      const headers = new Headers();
+      headers.set('X-Dropbox-Request-Id', '<b>dbx-request-123</b>&"');
+      const response = new Response('gateway timeout', {
+        status: 504,
+        statusText: 'Gateway Timeout',
+        headers,
+      });
+      const provider = {
+        id: SyncProviderId.Dropbox,
+        isReady: jasmine.createSpy('isReady').and.resolveTo(false),
+        getAuthHelper: jasmine.createSpy('getAuthHelper').and.resolveTo({
+          authUrl: 'https://www.dropbox.com/oauth2/authorize',
+          codeVerifier: 'code-verifier',
+          verifyCodeChallenge: jasmine
+            .createSpy('verifyCodeChallenge')
+            .and.rejectWith(new HttpNotOkAPIError(response, 'gateway timeout')),
+        }),
+      } as unknown as SyncProviderBase<SyncProviderId.Dropbox>;
+      mockProviderManager.getProviderById.and.resolveTo(provider);
+      mockMatDialog.open.and.returnValue({
+        afterClosed: () => of('auth-code'),
+      } as unknown as MatDialogRef<DialogGetAndEnterAuthCodeComponent>);
+
+      const result = await service.configuredAuthForSyncProviderIfNecessary(
+        SyncProviderId.Dropbox,
+      );
+
+      expect(result).toEqual({ wasConfigured: false });
+      expect(mockSnackService.open).toHaveBeenCalledWith({
+        msg: T.F.SYNC.S.AUTH_SERVICE_UNAVAILABLE_WITH_REFERENCE,
+        translateParams: {
+          status: '504',
+          reference: '&lt;b&gt;dbx-request-123&lt;/b&gt;&amp;&quot;',
+        },
+        type: 'ERROR',
+        config: { duration: 0 },
+      });
+    });
+
+    it('shows a temporary service error without a reference when none is returned', async () => {
+      const response = new Response('internal server error', {
+        status: 500,
+        statusText: 'Internal Server Error',
+      });
+      const provider = {
+        id: SyncProviderId.Dropbox,
+        isReady: jasmine.createSpy('isReady').and.resolveTo(false),
+        getAuthHelper: jasmine.createSpy('getAuthHelper').and.resolveTo({
+          authUrl: 'https://www.dropbox.com/oauth2/authorize',
+          codeVerifier: 'code-verifier',
+          verifyCodeChallenge: jasmine
+            .createSpy('verifyCodeChallenge')
+            .and.rejectWith(new HttpNotOkAPIError(response, 'internal server error')),
+        }),
+      } as unknown as SyncProviderBase<SyncProviderId.Dropbox>;
+      mockProviderManager.getProviderById.and.resolveTo(provider);
+      mockMatDialog.open.and.returnValue({
+        afterClosed: () => of('auth-code'),
+      } as unknown as MatDialogRef<DialogGetAndEnterAuthCodeComponent>);
+
+      await service.configuredAuthForSyncProviderIfNecessary(SyncProviderId.Dropbox);
+
+      expect(mockSnackService.open).toHaveBeenCalledWith({
+        msg: T.F.SYNC.S.AUTH_SERVICE_UNAVAILABLE,
+        translateParams: { status: '500' },
+        type: 'ERROR',
+        config: { duration: 0 },
+      });
+    });
+  });
+
   describe('websocket integration', () => {
     it('should disconnect websocket when provider changes away from SuperSync', async () => {
       configSubject.next(createMockSyncConfig(SyncProviderId.WebDAV));
diff --git a/src/app/imex/sync/sync-wrapper.service.ts b/src/app/imex/sync/sync-wrapper.service.ts
index 514f87b3c9..34205dbb76 100644
--- a/src/app/imex/sync/sync-wrapper.service.ts
+++ b/src/app/imex/sync/sync-wrapper.service.ts
@@ -53,6 +53,7 @@ import { LegacyPfDbService } from '../../core/persistence/legacy-pf-db.service';
 import { T } from '../../t.const';
 import { getSyncErrorStr } from './get-sync-error-str';
 import { getErrorTxt } from '../../util/get-error-text';
+import { escapeHtml } from '../../util/escape-html';
 import { DialogGetAndEnterAuthCodeComponent } from './dialog-get-and-enter-auth-code/dialog-get-and-enter-auth-code.component';
 import { DialogConflictResolutionResult } from './sync.model';
 import { DialogSyncConflictComponent } from './dialog-sync-conflict/dialog-sync-conflict.component';
@@ -1151,7 +1152,16 @@ export class SyncWrapperService {
     } catch (error) {
       SyncLog.err(`Failed to configure auth for provider ${providerId}:`, error);
       const httpErr = error instanceof HttpNotOkAPIError ? error : null;
-      const isTokenExchangeError = httpErr?.response?.status === 400;
+      const httpStatus = httpErr?.response.status;
+      const isTokenExchangeError = httpStatus === 400;
+      const isAuthServiceUnavailable =
+        httpStatus !== undefined && httpStatus >= 500 && httpStatus < 600;
+      // Dropbox recommends retaining this response ID for support investigations.
+      // https://developers.dropbox.com/error-handling-guide#logging
+      const providerRequestId =
+        providerId === SyncProviderId.Dropbox
+          ? httpErr?.response.headers.get('X-Dropbox-Request-Id')
+          : null;
       // A OneDrive token-exchange 400 is almost always a misconfigured
       // Microsoft Entra app registration (typically "Allow public client
       // flows" disabled), not a mistyped/expired code — the authorize step
@@ -1165,6 +1175,14 @@ export class SyncWrapperService {
         translateParams = { error: httpErr?.detail || getErrorTxt(error) };
       } else if (isTokenExchangeError) {
         msg = T.F.SYNC.S.INVALID_AUTH_CODE;
+      } else if (isAuthServiceUnavailable) {
+        translateParams = { status: String(httpStatus) };
+        if (providerRequestId) {
+          msg = T.F.SYNC.S.AUTH_SERVICE_UNAVAILABLE_WITH_REFERENCE;
+          translateParams.reference = escapeHtml(providerRequestId);
+        } else {
+          msg = T.F.SYNC.S.AUTH_SERVICE_UNAVAILABLE;
+        }
       } else {
         msg = T.F.SYNC.S.AUTH_SETUP_FAILED;
       }
diff --git a/src/app/t.const.ts b/src/app/t.const.ts
index 5226110a50..833ac64e03 100644
--- a/src/app/t.const.ts
+++ b/src/app/t.const.ts
@@ -1636,6 +1636,9 @@ const T = {
       S: {
         ALREADY_IN_SYNC: 'F.SYNC.S.ALREADY_IN_SYNC',
         ARCHIVE_OPERATION_FAILED: 'F.SYNC.S.ARCHIVE_OPERATION_FAILED',
+        AUTH_SERVICE_UNAVAILABLE: 'F.SYNC.S.AUTH_SERVICE_UNAVAILABLE',
+        AUTH_SERVICE_UNAVAILABLE_WITH_REFERENCE:
+          'F.SYNC.S.AUTH_SERVICE_UNAVAILABLE_WITH_REFERENCE',
         AUTH_SETUP_FAILED: 'F.SYNC.S.AUTH_SETUP_FAILED',
         AUTH_TOKEN_REJECTED: 'F.SYNC.S.AUTH_TOKEN_REJECTED',
         BTN_CONFIGURE: 'F.SYNC.S.BTN_CONFIGURE',
diff --git a/src/assets/i18n/en.json b/src/assets/i18n/en.json
index 49b2b03fe2..5402dd9acd 100644
--- a/src/assets/i18n/en.json
+++ b/src/assets/i18n/en.json
@@ -1589,7 +1589,9 @@
       "S": {
         "ALREADY_IN_SYNC": "Already in sync",
         "ARCHIVE_OPERATION_FAILED": "Archive operation failed. Some cleanup may not have completed.",
-        "AUTH_SETUP_FAILED": "Failed to set up authentication. Please try again. If you're using the web app, make sure you're accessing it over HTTPS. Otherwise, please report this as a bug if it keeps happening.",
+        "AUTH_SERVICE_UNAVAILABLE": "The authentication service is temporarily unavailable (HTTP {{status}}). Please try again.",
+        "AUTH_SERVICE_UNAVAILABLE_WITH_REFERENCE": "The authentication service is temporarily unavailable (HTTP {{status}}). Please try again. Reference: {{reference}}.",
+        "AUTH_SETUP_FAILED": "Failed to set up authentication. Please try again. If it keeps happening, check your connection and report the error details.",
         "AUTH_TOKEN_REJECTED": "Sync token was rejected by the server: {{reason}}. Please get a new token.",
         "BTN_CONFIGURE": "Configure",
         "BTN_FORCE_OVERWRITE": "Force Overwrite",