can not log in

Sign in through the Microsoft 365 portal and explicitly choose Work or school account, because using a similarly named personal Microsoft account can prevent access to the organization’s services.

Try the correct work-account sign-in

1. Open a private/incognito browser window.
2. Go to www.microsoft365.com and select Sign in.
3. Enter your complete work email address.
4. If asked which account to use, select Work or school account, not Personal account.
5. After signing in, open App launcher → Outlook. This is the supported web sign-in route for Microsoft 365 and Outlook on the web.^1^

Because the same account fails on both phone and desktop—and cannot access other Microsoft 365 apps—do not reinstall Outlook or troubleshoot an individual device yet.

If the account may be locked or the password may have expired

Use the work-account password reset page:

https://passwordreset.microsoftonline.com

Complete the reset and then retry the private browser window. Self-service reset works only if your organization enabled it and previously registered recovery information for your account. Otherwise, your Microsoft 365 administrator must reset the password.^2^

Ask your workplace IT administrator to check the account

If the correct portal and password reset do not restore access, send this checklist to your IT department. These are administrator-only checks:

1. In Microsoft Entra admin center → Entra ID → Users, locate your account and confirm:
   • The account exists.
   • Profile → Settings → Block sign in is set to No.
   • The password is not expired or locked.
   • Multifactor authentication and Conditional Access are not blocking access.
2. Reset the account password if necessary.
3. Check that the appropriate Microsoft 365 and Exchange license is assigned for Outlook access. A missing license can prevent access to licensed applications, although it does not by itself establish why every Microsoft 365 sign-in is failing.^3^

The administrator should also check Microsoft 365 admin center → Health → Service health for an active Microsoft 365, Microsoft Entra, Outlook, or Exchange Online incident. If administrators cannot sign in either, they can use Microsoft’s public service-status page instead.^4^

If service health is normal, IT should review your Microsoft Entra sign-in logs and open a Microsoft 365 support request with the time of the failed attempt. Do not post your email address, password, verification code, or tenant details publicly.

References

1. How to sign in to Outlook on the web | Microsoft Support
2. Forgot password to sign in to Microsoft 365, Intune, or Azure
3. Problems signing in to a Microsoft application
4. How to check Microsoft 365 service health