Authenthicator app doesnt recognize my work email adress.

Question

I need to do a backup on a android phone of my Authenticator app,
but to do that i must login to microsoft account within the app.
it says there is no such address.
its a business email and i have no private one.
of course it exists, i use it every day.
Authenthicator app doesnt recognize my work email adress so i cant log in to do a backup.
please advice.