Hi,
Thanks for reaching out to Microsoft Q&A.
Have you tried...
- Restarting the phone
- Uninstall-Install the app
- Remove and add the email account
https://learn.microsoft.com/en-us/troubleshoot/azure/active-directory/troubleshoot-azure-mfa-issue
Please Upvote and Accept as answer if the reply was helpful, this will be benefitting the other community members who go through the same issue.