I cannot access Outlook

Question

Each time I try to use Outlook I receive an error message.

Answer 1

Hi! Sorry to hear you’re having trouble with this situation. Could you please share more information about the exact error message you see when trying to sign in to Outlook.com? If possible, please also share a screenshot of the error, as that can help identify whether this is related to the browser, the account, or a security check.

In the meantime, please try these steps: clear your browser’s cookies and cache, then close and reopen the browser before trying again; open Outlook.com in an InPrivate window in Microsoft Edge; if your account has a secondary alias (another email address or phone number linked for sign-in), try using that instead of the primary one; and test from a different network, such as a mobile hotspot, to rule out an IP or network-related sign-in block.

Answer 2

Use the following steps to troubleshoot Outlook access issues, starting with the least intrusive options:

1. Sign out everywhere
   • If Outlook.com access is failing in both web and the new Outlook for Windows, sign out of all Microsoft sessions using the "Sign Out of Everywhere" option, then wait and sign in again. This has resolved server-side issues such as TooManyObjectsOpenedError for other Outlook.com users.
2. Check if the mailbox is disabled (work/school accounts)
   • If this is a work or school account and Outlook on the web shows errors like HTTP 404 with esrc: StartupData, the mailbox may be disabled even if the Entra ID (Azure AD) account is active.
   • In this case, contact the tenant administrator and ask them to:
     • Check whether the mailbox is disabled (e.g., AccountDisabled : True).
     • Re-enable the mailbox if it is disabled.
   • After the mailbox is re-enabled, try signing in again to Outlook on the web.
3. Clear browser and session issues
   • Sign out of all Microsoft sessions in the browser.
   • Clear the browser cache (for example, press Ctrl + Shift + Delete and clear browsing data).
   • Open a new InPrivate/Incognito window (Ctrl + Shift + N) and try Outlook on the web again.
   • If Outlook works in InPrivate mode, disable browser extensions such as ad blockers or VPNs that might interfere with Outlook.
4. If Outlook will not open on the PC client
   • If the Outlook desktop app will not open at all, fully uninstall Microsoft 365/Office from the PC and reinstall it from the subscription. This has resolved cases where Outlook suddenly stopped opening even after repair/reset.

If the issue persists, note the exact error message shown in Outlook on the web or the Outlook client and provide it to the administrator or support, as specific error codes (for example, mailbox disabled, too many objects opened) determine the next steps.

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References:

• What to do when Outlook will not open on my PC? - Microsoft Q&A
• Outlook.com address returning TooManyObjectsOpenedError - Microsoft Q&A
• Not able to have access to my email ! - Microsoft Q&A
• Unable to sign into account - says I am not connected to Internet but I am - Microsoft Q&A