I have a 20k mailbox Exchange environment.   I get an occasional report from a user where they get the standard Autodiscover prompt.. Allow autodiscover.mydomain to make changes to e-mail address.

The strange thing is occasionally it will be for an e-mail address different than the mailbox(es) configured in Outlook.

Any ideas how this happens?

The strange thing is occasionally it will be for an e-mail address different than the mailbox(es) configured in Outlook.

Check/modify the UPN for these accounts. You might have to add their email address as the default UPN. If you are working with a large number of users, you'll have to bulk modify these accounts in powershell. 

                                                                  

Step by Step Screencasts and Video Tutorials

• Edited by NetoMeter Screencasts 14 hours 44 minutes ago

The strange thing is occasionally it will be for an e-mail address different than the mailbox(es) configured in Outlook.

Check/modify the UPN for these accounts. You might have to add their email address as the default UPN. If you are working with a large number of users, you'll have to bulk modify these accounts in powershell. 

                                                                  

Step by Step Screencasts and Video Tutorials

• Edited by NetoMeter Screencasts Thursday, March 05, 2015 12:50 AM

Thanks for the input,

I checked the UPN of the users impacted, and their UPN matches their e-mail address already.  One thing I did identify is these users are coming through some type of network device that is masking their workstation IP so that in the Exchange IIS logs these users sessions are all coming from the same IP address.   But wouldn't it be keeping track of the session via user somehow?

Jason