Managing personal Outlook.com account settings, security, and privacy
Hi,
May I ask if you are trying to sign in using the New Outlook app, Classic Outlook, or on the Web?
Has this happened only recently?
Are you able to sign in to your account before?
In the meantime, please try restarting your PC. This will help delete the temporary cache and help fix the temporary issue.
I look forward to your response.
Stay Safe!