Need help with user access

Question

Error message is:

UTC Date: 2026-02-12T04:02:28.663Z
Client Id: <Removed>
Session Id: <Removed>
Client Version: 20260130003.07
BootResult: fail
Back Filled Errors: None
err: Error: 401
esrc: StartupData
et: ServerError
estack: Error: 401
    at Object.w [as createStatusErrorMessage] (https://res.public.onecdn.static.microsoft/owamail/hashed-v1/singleCss/scripts/owa.mailindex.b3274fb9.js:2:8809)
    at https://res.public.onecdn.static.microsoft/owamail/hashed-v1/singleCss/scripts/owa.mailindex.b3274fb9.js:2:41447
st: 401
efe: <Removed>

Answer 1

Hi @Josselyn Boudett

Thank you for posting your question in the Q&A Forum. 

The 401 error occurring during StartupData suggests that your initial authentication likely went through, but Exchange Online is denying permission to load the actual mailbox content. This is usually tied to backend provisioning or licensing rather than a simple password issue.

To rule out any local browser glitches first, please try signing in via an InPrivate/Incognito window. If that works, you just need to clear your browser's cache and cookies.

However, if the error persists, your Microsoft 365 admin will need to review the following on the tenant side:

• Confirm that an active Exchange Online license is assigned and that the mailbox is fully provisioned in the Exchange Admin Center.
• Check if there are any Conditional Access policies or sign-in blocks in Entra ID that might be triggering after the initial login.

If everything looks correct on their side, please ask your admin to open a Microsoft support ticket. Be sure to provide them with the UTC timestamp, Client ID, and Session ID from your error message so they can trace the backend logs.

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Answer 2

The error message you are encountering indicates a 401 Unauthorized error, which typically means that the user is not authorized to access the requested resource. This can happen for several reasons, including:

1. Invalid Credentials: The user may have entered incorrect login details.
2. Insufficient Permissions: The user may not have the necessary permissions to access the application or resource.
3. Session Issues: There might be a problem with the user's session or token expiration.
4. Authentication Issues: The authentication method being used may not be supported or may require additional configuration.

To resolve this issue, consider the following steps:

• Verify that the user is using the correct credentials.
• Check the user's permissions and ensure they have access to the required resources.
• If applicable, prompt the user to re-authenticate or clear their session cookies and try again.
• Review any recent changes to the authentication settings that might affect access.

If the problem persists, further investigation into the server logs may be necessary to identify the root cause of the authorization failure.