This is usually caused by outdated saved credentials or a sign-in problem between Outlook and Microsoft 365. Clear the saved Office credentials in Windows Credential Manager, sign out of Office, sign back in, and complete any multi-factor prompt.
Common causes
Old saved credentials
After a password change, Windows keeps offering the old password.
Sign-in token problem
The Office sign-in can break, causing repeated prompts.
Multi-factor prompt not completed
The prompt may be hiding behind other windows.
Legacy account setup
Accounts set up with old connection methods don't work with modern Microsoft 365 sign-in.
How to fix it, step by step
- 1
Check for a hidden sign-in window
Look for a Microsoft sign-in window behind Outlook and complete it.
- 2
Clear saved credentials
Open Credential Manager > Windows Credentials and remove entries starting with MicrosoftOffice or containing your email.
- 3
Sign out and back in to Office
In Outlook, go to File > Office Account > Sign out, restart Outlook, and sign in again.
- 4
Update Office
Older Office builds have more sign-in issues.
- 5
Recreate the Outlook profile
If prompts continue, set up a new profile so the account uses modern sign-in.
When to call a technician
If prompts started suddenly for several people, there may be an account or tenant setting involved. We sort out Microsoft 365 sign-in and multi-factor settings for the whole office.
On-site support across Orange County · see our IT support, managed IT, Microsoft 365 support and cybersecurity services.
Frequently asked questions
Why does Outlook reject my correct password?
It's often trying old saved credentials or a legacy sign-in method rather than your new password.
Can a password prompt be a phishing attempt?
Yes. If a prompt looks unusual or appears in a browser from an email link, don't enter your password.
Does this happen after a password change?
Very often. Clearing saved credentials and signing in again usually fixes it.