Outlook for Android using UPN when sending a mail

Question

Hi everyone,

I have an on-premises Exchange Server. The UPN and the email address are different for every user (I don't really know why; my colleagues set it up like this long before I joined the team).

My Exchange Server is behind a proxy that performs an LDAP search before forwarding the request.

When adding my Exchange account on a mobile app, I need to enter the UPN in the username field and leave the domain field empty for the LDAP search to work.

On Gmail and Apple Mail, everything works fine.

However, on the Android app (and probably the iOS app as well), every time I try to send a new email, the app uses the UPN instead of the email address as the sender. This results in an error stating that I can't send emails as my UPN.

Interestingly, I can reply to emails without any issue.

I tried to find a way to change the primary alias used by the app, but the only articles I found were for online accounts and don't work for on-premises setups.

Does someone have an idea ?

Answer 1

Hello, @Louis VILLEMIN,

Welcome to the Microsoft Q&A platform!

Looks like the issue is more related to Outlook for mobile. Please kindly understand that the Outlook Management tag here we mainly focus on general issues about Outlook desktop client. Therefore, I would like to confirm with you that your account will not get the same error when logging into Outlook client as well as Outlook for Web. If your problem exists only in Outlook for Android. In order to better solve your problem, it's suggested to post your issue on this dedicated forum for Outlook for Mobile for more professional help. 

Thank you for your understanding and support.

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Alex Zhang