Every 90 days you are
required to re-register your MFA token. Preferably you have the Microsoft Authenticator App installed on your mobile phone as
Microsoft no longer supports SMS. But if you do not have a mobile phone, then calls from Microsoft are still an option for MFA. You can set it to call your work phone.
You are prompted with the
screens below
Input your work phone number and select Next. Follow the prompts to verify the call from Microsoft.
As of 9/15/23, Call and Text will still show as options for you when setting it up this way but Microsoft will be removing Text as an option any day