Users No longer Getting 2FA calls to Office Extensions

Question

We received reports from users that they are no longer getting calls to their office extension numbers to verify 2FA and log into their emails.

After Disabling 2FA, we tried to add office phone extension again, and after multiple tries we were able to add office phone, but did not receive any call when tried to log back in to Outlook next day.

Did anything change recently, where MS stopped supporting office phone extensions for MFA?

Answer 1

Hi, Extensions are no longer supported with MFA:

https://learn.microsoft.com/en-us/azure/active-directory/authentication/concept-authentication-phone-options#:%7E:text=Password%20reset%20and%20Azure%20AD%20Multi%2DFactor%20Authentication%20don%27t%20support%20phone%20extensions.%20Even%20in%20the%20%2B1%204251234567X12345%20format%2C%20extensions%20are%20removed%20before%20the%20call%20is%20placed.