Whether you’re using a personal microsoft account or a work/school account tied to microsoft entra id (azure ad/office 365), the solution usually comes down to cleaning up. Learn how to setup the microsoft authentication app with number matching push notifications to increase user security. You may be asked to reset your account password for security purposes, just select 'i don't have authenticator app right now' and use your recovery phone number or email.
It's to prevent someone that has your password (or other authenticator) from requesting a 2fa proof for a seperate session at the same time as you're about to log in. Rather than simply tapping yes to allow sign in, you will. You can resolve problems with microsoft authenticator by checking the tips in this article and reviewing some of the known errors.
If you are signing in on the same device where the authenticator app is installed, you can simply tap on the notification that appears and reply with yes or no to complete.