I can't sign in to my email anymore, authenticator doesn't work

I made a custom business email for work and had to put an authenticator on there to use it, but now when I try to log in it says enter a number on your outlook app and gives me a random number but there's no were to actually input that number be it on the outlook app or the authenticator, just stuck I'm getting an error code "500121" when I view details, any help would be appreciated

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