I was able to resolve the problem by deleting the Authenticator app from my phone, reinstalling it, and re-adding my work Microsoft account within the app. I decided not to re-add my personal Microsoft account within the app, and I don't know if the problem would recur if I did so.
Thanks again Dave for your comments.
I don't see how to mark this problem/thread as resolved, but if someone can point me in the right direction, I'll be happy to do so.