Using Outlook for Android for personal email and calendar management
Hi Debbie,
Can you try signing in at https://outlook.live.com from your phone's browser?
If you can access your emails there, the issue is probably with the Outlook app. Try going to Outlook > Settings > Select your account > Reset Account.
One quick question: are you completely locked out, or can you sign in but some emails are missing?
If you can't sign in at all, Microsoft's recovery tool might help: https://aka.ms/sign-in-helper