diff --git a/packages/twenty-server/jest.config.mjs b/packages/twenty-server/jest.config.mjs
index 22d28de204..bc6775f700 100644
--- a/packages/twenty-server/jest.config.mjs
+++ b/packages/twenty-server/jest.config.mjs
@@ -11,7 +11,7 @@ const jestConfig = {
   testEnvironment: 'node',
   setupFilesAfterEnv: ['./setupTests.ts'],
   transformIgnorePatterns: [
-    '/node_modules/(?!(file-type|@file-type|strtok3|token-types|@borewit|@tokenizer|uint8array-extras|read-next-line)/)',
+    '/node_modules/(?!(file-type|@file-type|strtok3|token-types|@borewit|@tokenizer|uint8array-extras|read-next-line|digest-fetch|md5|js-sha256|js-sha512|base-64|charenc|crypt)/)',
   ],
   testRegex: '.*\\.spec\\.ts$',
   transform: {
diff --git a/packages/twenty-server/package.json b/packages/twenty-server/package.json
index f60494cb99..f041d815bd 100644
--- a/packages/twenty-server/package.json
+++ b/packages/twenty-server/package.json
@@ -104,6 +104,7 @@
     "dataloader": "2.2.2",
     "date-fns": "2.30.0",
     "deep-equal": "2.2.3",
+    "digest-fetch": "^3.1.1",
     "dompurify": "3.3.3",
     "dotenv": "16.4.5",
     "exa-js": "^2.11.0",
@@ -179,7 +180,7 @@
     "temporal-polyfill": "^0.3.0",
     "transliteration": "2.3.5",
     "tsconfig-paths": "^4.2.0",
-    "tsdav": "^2.1.5",
+    "tsdav": "^2.2.0",
     "tslib": "2.8.1",
     "type-fest": "4.10.1",
     "typeorm": "patch:typeorm@0.3.20#./patches/typeorm+0.3.20.patch",
diff --git a/packages/twenty-server/src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/auth/__tests__/create-basic-digest-auth-fetch.spec.ts b/packages/twenty-server/src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/auth/__tests__/create-basic-digest-auth-fetch.spec.ts
new file mode 100644
index 0000000000..05e06a46e1
--- /dev/null
+++ b/packages/twenty-server/src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/auth/__tests__/create-basic-digest-auth-fetch.spec.ts
@@ -0,0 +1,82 @@
+import { createBasicDigestAuthFetch } from 'src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/auth/create-basic-digest-auth-fetch';
+
+const mockFetch = (handle: (init?: RequestInit) => Response) => {
+  const calls: (RequestInit | undefined)[] = [];
+  const fn = jest.fn(async (_input, init) => {
+    calls.push(init);
+
+    return handle(init);
+  });
+
+  return { calls, fn: fn as unknown as typeof fetch };
+};
+
+const digest401 = () =>
+  new Response('', {
+    status: 401,
+    headers: {
+      'WWW-Authenticate':
+        'Digest realm="NMMDav", qop="auth", nonce="n", opaque="o"',
+    },
+  });
+
+describe('createBasicDigestAuthFetch', () => {
+  it('attaches Basic on the first request so Basic-only servers succeed in one round trip', async () => {
+    const { calls, fn } = mockFetch(() => new Response('ok', { status: 207 }));
+
+    await createBasicDigestAuthFetch(
+      'Aladdin',
+      'open sesame',
+      fn,
+    )('https://example.test/cal/');
+
+    expect(calls).toHaveLength(1);
+    expect(new Headers(calls[0]?.headers).get('Authorization')).toBe(
+      `Basic ${Buffer.from('Aladdin:open sesame', 'utf8').toString('base64')}`,
+    );
+  });
+
+  it('upgrades to Digest on 401 and routes the retry through the supplied fetch, never globalThis.fetch', async () => {
+    const forbiddenGlobal = jest.fn(async () => {
+      throw new Error('globalThis.fetch must not be called');
+    });
+    const original = globalThis.fetch;
+
+    globalThis.fetch = forbiddenGlobal as unknown as typeof fetch;
+
+    try {
+      const { calls, fn } = mockFetch((init) =>
+        new Headers(init?.headers).get('Authorization')?.startsWith('Digest ')
+          ? new Response('ok', { status: 207 })
+          : digest401(),
+      );
+
+      const response = await createBasicDigestAuthFetch(
+        'user',
+        'pass',
+        fn,
+      )('https://example.test/cal/', { method: 'PROPFIND' });
+
+      expect(response.status).toBe(207);
+      expect(calls).toHaveLength(2);
+      expect(new Headers(calls[1]?.headers).get('Authorization')).toMatch(
+        /^Digest .*realm="NMMDav".*opaque="o"/,
+      );
+      expect(forbiddenGlobal).not.toHaveBeenCalled();
+    } finally {
+      globalThis.fetch = original;
+    }
+  });
+
+  it('surfaces the 401 when the Digest retry is also rejected', async () => {
+    const { fn } = mockFetch(() => digest401());
+
+    const response = await createBasicDigestAuthFetch(
+      'user',
+      'wrong-pass',
+      fn,
+    )('https://example.test/');
+
+    expect(response.status).toBe(401);
+  });
+});
diff --git a/packages/twenty-server/src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/auth/create-basic-digest-auth-fetch.ts b/packages/twenty-server/src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/auth/create-basic-digest-auth-fetch.ts
new file mode 100644
index 0000000000..a13e39fb9b
--- /dev/null
+++ b/packages/twenty-server/src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/auth/create-basic-digest-auth-fetch.ts
@@ -0,0 +1,37 @@
+import DigestFetch from 'digest-fetch';
+import { getBasicAuthHeaders } from 'tsdav';
+import { isDefined } from 'twenty-shared/utils';
+
+/**
+ * Decorates a base fetch with HTTP Basic + Digest authentication.
+ *
+ * Delegates RFC 7235 / RFC 7616 challenge parsing, hash computation,
+ * and 401-then-retry orchestration to `digest-fetch`
+ */
+export const createBasicDigestAuthFetch = (
+  username: string,
+  password: string,
+  baseFetch: typeof globalThis.fetch = globalThis.fetch,
+): typeof globalThis.fetch => {
+  const digestClient = new DigestFetch(username, password);
+
+  digestClient.getClient = async () => baseFetch;
+
+  const { authorization: basicAuthorization } = getBasicAuthHeaders({
+    username,
+    password,
+  });
+
+  return async (input, init) => {
+    const headers = new Headers(init?.headers);
+
+    if (!headers.has('Authorization') && isDefined(basicAuthorization)) {
+      headers.set('Authorization', basicAuthorization);
+    }
+
+    return digestClient.fetch(input, {
+      ...init,
+      headers,
+    }) as Promise<Response>;
+  };
+};
diff --git a/packages/twenty-server/src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/caldav.client.ts b/packages/twenty-server/src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/caldav.client.ts
index 7a19208c06..1e1aca1c2c 100644
--- a/packages/twenty-server/src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/caldav.client.ts
+++ b/packages/twenty-server/src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/caldav.client.ts
@@ -9,10 +9,10 @@ import {
   DAVNamespaceShort,
   type DAVObject,
   fetchCalendars,
-  getBasicAuthHeaders,
   syncCollection,
 } from 'tsdav';
 
+import { createBasicDigestAuthFetch } from 'src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/auth/create-basic-digest-auth-fetch';
 import { icalDataExtractPropertyValue } from 'src/modules/calendar/calendar-event-import-manager/drivers/caldav/lib/utils/icalDataExtractPropertyValue';
 import { CalDavGetEventsService } from 'src/modules/calendar/calendar-event-import-manager/drivers/caldav/services/caldav-get-events.service';
 import { CalendarEventParticipantResponseStatus } from 'src/modules/calendar/common/standard-objects/calendar-event-participant.workspace-entity';
@@ -62,20 +62,16 @@ type CalDAVGetEventsResponse = {
 export class CalDAVClient {
   private credentials: CalendarCredentials;
   private logger: Logger;
+  private fetchOverride: typeof fetch;
 
   constructor(credentials: CalendarCredentials) {
     this.credentials = credentials;
     this.logger = new Logger(CalDAVClient.name);
-  }
-
-  private getTsdavRequestConfig() {
-    return {
-      headers: getBasicAuthHeaders({
-        username: this.credentials.username,
-        password: this.credentials.password,
-      }),
-      fetch: this.credentials.fetch,
-    };
+    this.fetchOverride = createBasicDigestAuthFetch(
+      credentials.username,
+      credentials.password,
+      credentials.fetch ?? globalThis.fetch,
+    );
   }
 
   private hasFileExtension(url: string): boolean {
@@ -110,7 +106,7 @@ export class CalDAVClient {
           password: this.credentials.password,
         },
       },
-      ...this.getTsdavRequestConfig(),
+      fetch: this.fetchOverride,
     });
   }
 
@@ -120,7 +116,7 @@ export class CalDAVClient {
 
       const calendars = (await fetchCalendars({
         account,
-        ...this.getTsdavRequestConfig(),
+        fetch: this.fetchOverride,
       })) as (Omit<DAVCalendar, 'displayName'> & {
         displayName?: string | Record<string, unknown>;
       })[];
@@ -156,7 +152,7 @@ export class CalDAVClient {
 
     const calendars = await fetchCalendars({
       account,
-      ...this.getTsdavRequestConfig(),
+      fetch: this.fetchOverride,
     });
 
     const eventCalendar = calendars.find((calendar) =>
@@ -365,7 +361,7 @@ export class CalDAVClient {
           },
           syncLevel: 1,
           ...(syncToken ? { syncToken } : {}),
-          ...this.getTsdavRequestConfig(),
+          fetch: this.fetchOverride,
         });
 
         const allEvents: FetchedCalendarEvent[] = [];
@@ -384,7 +380,7 @@ export class CalDAVClient {
               },
               objectUrls: objectUrls,
               depth: '1',
-              ...this.getTsdavRequestConfig(),
+              fetch: this.fetchOverride,
             });
 
             for (const calendarObject of calendarObjects) {
@@ -432,7 +428,7 @@ export class CalDAVClient {
           const account = await this.getAccount();
           const updatedCalendars = await fetchCalendars({
             account,
-            ...this.getTsdavRequestConfig(),
+            fetch: this.fetchOverride,
           });
           const updatedCalendar = updatedCalendars.find(
             (cal) => cal.url === calendar.url,
diff --git a/yarn.lock b/yarn.lock
index 4a3054ca98..9b56874d56 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -31351,6 +31351,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"base-64@npm:^0.1.0":
+  version: 0.1.0
+  resolution: "base-64@npm:0.1.0"
+  checksum: 10c0/fe0dcf076e823f04db7ee9b02495be08a91c445fbc6db03cb9913be9680e2fcc0af8b74459041fe08ad16800b1f65a549501d8f08696a8a6d32880789b7de69d
+  languageName: node
+  linkType: hard
+
 "base32-encode@npm:^0.1.0 || ^1.0.0":
   version: 1.2.0
   resolution: "base32-encode@npm:1.2.0"
@@ -32676,6 +32683,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"charenc@npm:0.0.2":
+  version: 0.0.2
+  resolution: "charenc@npm:0.0.2"
+  checksum: 10c0/a45ec39363a16799d0f9365c8dd0c78e711415113c6f14787a22462ef451f5013efae8a28f1c058f81fc01f2a6a16955f7a5fd0cd56247ce94a45349c89877d8
+  languageName: node
+  linkType: hard
+
 "check-disk-space@npm:3.4.0":
   version: 3.4.0
   resolution: "check-disk-space@npm:3.4.0"
@@ -34430,15 +34444,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"cross-fetch@npm:4.1.0, cross-fetch@npm:~4.1.0":
-  version: 4.1.0
-  resolution: "cross-fetch@npm:4.1.0"
-  dependencies:
-    node-fetch: "npm:^2.7.0"
-  checksum: 10c0/628b134ea27cfcada67025afe6ef1419813fffc5d63d175553efa75a2334522d450300a0f3f0719029700da80e96327930709d5551cf6deb39bb62f1d536642e
-  languageName: node
-  linkType: hard
-
 "cross-fetch@npm:^3.0.4, cross-fetch@npm:^3.1.5":
   version: 3.1.8
   resolution: "cross-fetch@npm:3.1.8"
@@ -34448,6 +34453,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"cross-fetch@npm:~4.1.0":
+  version: 4.1.0
+  resolution: "cross-fetch@npm:4.1.0"
+  dependencies:
+    node-fetch: "npm:^2.7.0"
+  checksum: 10c0/628b134ea27cfcada67025afe6ef1419813fffc5d63d175553efa75a2334522d450300a0f3f0719029700da80e96327930709d5551cf6deb39bb62f1d536642e
+  languageName: node
+  linkType: hard
+
 "cross-inspect@npm:1.0.0":
   version: 1.0.0
   resolution: "cross-inspect@npm:1.0.0"
@@ -34497,6 +34511,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"crypt@npm:0.0.2":
+  version: 0.0.2
+  resolution: "crypt@npm:0.0.2"
+  checksum: 10c0/adbf263441dd801665d5425f044647533f39f4612544071b1471962209d235042fb703c27eea2795c7c53e1dfc242405173003f83cf4f4761a633d11f9653f18
+  languageName: node
+  linkType: hard
+
 "crypto-browserify@npm:^3.0.0":
   version: 3.12.0
   resolution: "crypto-browserify@npm:3.12.0"
@@ -35848,6 +35869,18 @@ __metadata:
   languageName: node
   linkType: hard
 
+"digest-fetch@npm:^3.1.1":
+  version: 3.1.1
+  resolution: "digest-fetch@npm:3.1.1"
+  dependencies:
+    base-64: "npm:^0.1.0"
+    js-sha256: "npm:^0.9.0"
+    js-sha512: "npm:^0.8.0"
+    md5: "npm:^2.3.0"
+  checksum: 10c0/c1f409a4a11406ea4161aef91236b326c8a366d7769ca100c18d7a19942af8f7e0d439734e83e53097ebda793f4baf6acb1664d1eaffc11bfcc0ec5808a3c0fb
+  languageName: node
+  linkType: hard
+
 "dir-compare@npm:^4.2.0":
   version: 4.2.0
   resolution: "dir-compare@npm:4.2.0"
@@ -42785,7 +42818,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"is-buffer@npm:^1.1.0":
+"is-buffer@npm:^1.1.0, is-buffer@npm:~1.1.6":
   version: 1.1.6
   resolution: "is-buffer@npm:1.1.6"
   checksum: 10c0/ae18aa0b6e113d6c490ad1db5e8df9bdb57758382b313f5a22c9c61084875c6396d50bbf49315f5b1926d142d74dfb8d31b40d993a383e0a158b15fea7a82234
@@ -45262,6 +45295,20 @@ __metadata:
   languageName: node
   linkType: hard
 
+"js-sha256@npm:^0.9.0":
+  version: 0.9.0
+  resolution: "js-sha256@npm:0.9.0"
+  checksum: 10c0/f20b9245f6ebe666f42ca05536f777301132fb1aa7fbc22f10578fa302717a6cca507344894efdeaf40a011256eb2f7d517b94ac7105bd5cf087fa61551ad634
+  languageName: node
+  linkType: hard
+
+"js-sha512@npm:^0.8.0":
+  version: 0.8.0
+  resolution: "js-sha512@npm:0.8.0"
+  checksum: 10c0/066fab16e14bd5dccff7c1cfca5961067ab00bb5e4eb0666d4fab8a669c0448663ccc982491cfe05f55cb693ed2722d40e6ee679a7b12e4006a6b358c17ddce8
+  languageName: node
+  linkType: hard
+
 "js-tokens@npm:^3.0.0 || ^4.0.0, js-tokens@npm:^4.0.0":
   version: 4.0.0
   resolution: "js-tokens@npm:4.0.0"
@@ -47397,6 +47444,17 @@ __metadata:
   languageName: node
   linkType: hard
 
+"md5@npm:^2.3.0":
+  version: 2.3.0
+  resolution: "md5@npm:2.3.0"
+  dependencies:
+    charenc: "npm:0.0.2"
+    crypt: "npm:0.0.2"
+    is-buffer: "npm:~1.1.6"
+  checksum: 10c0/14a21d597d92e5b738255fbe7fe379905b8cb97e0a49d44a20b58526a646ec5518c337b817ce0094ca94d3e81a3313879c4c7b510d250c282d53afbbdede9110
+  languageName: node
+  linkType: hard
+
 "mdast-util-find-and-replace@npm:^3.0.0":
   version: 3.0.2
   resolution: "mdast-util-find-and-replace@npm:3.0.2"
@@ -60148,15 +60206,14 @@ __metadata:
   languageName: node
   linkType: hard
 
-"tsdav@npm:^2.1.5":
-  version: 2.1.8
-  resolution: "tsdav@npm:2.1.8"
+"tsdav@npm:^2.2.0":
+  version: 2.2.0
+  resolution: "tsdav@npm:2.2.0"
   dependencies:
     base-64: "npm:1.0.0"
-    cross-fetch: "npm:4.1.0"
     debug: "npm:4.4.3"
     xml-js: "npm:1.6.11"
-  checksum: 10c0/bb0ff3021483ca2a1878c45aeb86cf27c0d03973dabd1dd547825e98de865b840d7a47662e277a251fabf9a39d521c13ea8a520807ce62fc3c8cd7a1a13710a2
+  checksum: 10c0/39dbe70c7e0bb1e5d48d776a15221d1f43c0e8165c7a1af3679e1c0517474ad133daf34763e19f79b7e365e54e3ff24b777f2198d2aedb6422c127a9841bf91c
   languageName: node
   linkType: hard
 
@@ -60702,6 +60759,7 @@ __metadata:
     dataloader: "npm:2.2.2"
     date-fns: "npm:2.30.0"
     deep-equal: "npm:2.2.3"
+    digest-fetch: "npm:^3.1.1"
     dompurify: "npm:3.3.3"
     dotenv: "npm:16.4.5"
     exa-js: "npm:^2.11.0"
@@ -60778,7 +60836,7 @@ __metadata:
     temporal-polyfill: "npm:^0.3.0"
     transliteration: "npm:2.3.5"
     tsconfig-paths: "npm:^4.2.0"
-    tsdav: "npm:^2.1.5"
+    tsdav: "npm:^2.2.0"
     tslib: "npm:2.8.1"
     twenty-client-sdk: "workspace:*"
     twenty-emails: "workspace:*"