Dear Expertise,
In my on-premises Exchange environment, some users are unable to log into Outlook mobile devices. However, these same users can log in using other mobile email apps such as Gmail or the default email app through the email address.
Here's the scenario:
A user's email address/SMTP is "active.jhon@abc.com" and their logon address/UPN is "actusr@xyz.org". The user is unable to log in to mobile Outlook using the email address/SMTP "active.jhon@abc.com", but they can successfully log in using only their logon address/UPN "actusr@xyz.org" if they select it as the email address in mobile outlook.
I have also tested using Microsoft Connectivity Analyzer, and it passed. However, users are still unable to log in to mobile Outlook using the "active.jhon@abc.com" address, while other mail apps can log in successfully. I have checked all URLs, and they are configured perfectly.
If I am not mistake, user should be to login through both email address and UPN.
How can I solve it.