diff --git a/code/core/src/common/utils/get-storybook-refs.test.ts b/code/core/src/common/utils/get-storybook-refs.test.ts
new file mode 100644
index 000000000000..9c1c4f540945
--- /dev/null
+++ b/code/core/src/common/utils/get-storybook-refs.test.ts
@@ -0,0 +1,35 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { checkRef } from './get-storybook-refs';
+
+describe('checkRef', () => {
+  afterEach(() => vi.restoreAllMocks());
+
+  it('returns true when fetch returns 200', async () => {
+    vi.spyOn(global, 'fetch').mockResolvedValue({
+      ok: true,
+      status: 200,
+      json: async () => ({}),
+    } as Response);
+    expect(await checkRef('https://chromatic.com')).toBe(true);
+  });
+
+  it('returns false when fetch returns 401', async () => {
+    vi.spyOn(global, 'fetch').mockResolvedValue({ ok: false, status: 401 } as Response);
+    expect(await checkRef('https://chromatic.com')).toBe(false);
+  });
+
+  it('returns false when fetch returns 200 with loginUrl', async () => {
+    vi.spyOn(global, 'fetch').mockResolvedValue({
+      ok: true,
+      status: 200,
+      json: async () => ({ loginUrl: 'https://chromatic.com/login' }),
+    } as Response);
+    expect(await checkRef('https://chromatic.com')).toBe(false);
+  });
+
+  it('returns false when fetch fails', async () => {
+    vi.spyOn(global, 'fetch').mockRejectedValue(new Error('Network error'));
+    expect(await checkRef('https://chromatic.com')).toBe(false);
+  });
+});
diff --git a/code/core/src/common/utils/get-storybook-refs.ts b/code/core/src/common/utils/get-storybook-refs.ts
index 457025541997..c6e1d10d1427 100644
--- a/code/core/src/common/utils/get-storybook-refs.ts
+++ b/code/core/src/common/utils/get-storybook-refs.ts
@@ -58,7 +58,7 @@ export const getAutoRefs = async (options: Options): Promise<Record<string, Ref>
   );
 };
 
-const checkRef = (url: string) =>
+export const checkRef = (url: string) =>
   fetch(`${url}/iframe.html`).then(
     async ({ ok, status }) => {
       if (ok) {
diff --git a/code/core/src/manager-api/modules/refs.ts b/code/core/src/manager-api/modules/refs.ts
index 586453443c05..151003529eed 100644
--- a/code/core/src/manager-api/modules/refs.ts
+++ b/code/core/src/manager-api/modules/refs.ts
@@ -118,6 +118,17 @@ async function handleRequest(
       throw new Error('Unexpected boolean response');
     }
     if (!response.ok) {
+      // Check for 401 responses that may contain loginUrl
+      if (response.status === 401) {
+        try {
+          const json = await response.json();
+          if (json.loginUrl) {
+            return { loginUrl: json.loginUrl };
+          }
+        } catch {
+          // Fall through to error handling if JSON parsing fails
+        }
+      }
       throw new Error(`Unexpected response not OK: ${response.statusText}`);
     }
 
diff --git a/code/core/src/manager-api/tests/refs.test.ts b/code/core/src/manager-api/tests/refs.test.ts
index bc337d3a7497..d3ec49e7cf7b 100644
--- a/code/core/src/manager-api/tests/refs.test.ts
+++ b/code/core/src/manager-api/tests/refs.test.ts
@@ -73,6 +73,7 @@ function createMockStore(initialState: Partial<State> = {}) {
 
 interface ResponseResult {
   ok?: boolean;
+  status?: number;
   err?: Error;
   response?: () => never | object | Promise<object>;
 }
@@ -86,13 +87,14 @@ type ResponseKeys =
   | 'metadata';
 
 function respond(result: ResponseResult): Promise<Response> {
-  const { err, ok, response } = result;
+  const { err, ok, status, response } = result;
   if (err) {
     return Promise.reject(err);
   }
 
   return Promise.resolve({
     ok: ok ?? !!response,
+    status: status ?? (ok ? 200 : 500),
     json: response,
   } as Response);
 }
@@ -784,6 +786,52 @@ describe('Refs API', () => {
       `);
     });
 
+    it('checks refs (auth with 401)', async () => {
+      // given
+      const { api } = initRefs({ provider, store } as any, { runCheck: false });
+
+      setupResponses({
+        indexPrivate: {
+          ok: false,
+          status: 401,
+          response: async () => ({ loginUrl: 'https://example.com/login' }),
+        },
+        storiesPrivate: {
+          ok: false,
+          status: 401,
+          response: async () => ({ loginUrl: 'https://example.com/login' }),
+        },
+        metadata: {
+          ok: false,
+          status: 401,
+          response: async () => ({ loginUrl: 'https://example.com/login' }),
+        },
+      });
+
+      await api.checkRef({
+        id: 'fake',
+        url: 'https://example.com',
+        title: 'Fake',
+      });
+
+      expect(store.setState.mock.calls[0][0]).toMatchInlineSnapshot(`
+        {
+          "refs": {
+            "fake": {
+              "filteredIndex": undefined,
+              "id": "fake",
+              "index": undefined,
+              "internal_index": undefined,
+              "loginUrl": "https://example.com/login",
+              "title": "Fake",
+              "type": "auto-inject",
+              "url": "https://example.com",
+            },
+          },
+        }
+      `);
+    });
+
     it('checks refs (basic-auth)', async () => {
       // given
       const { api } = initRefs({ provider, store } as any, { runCheck: false });