Exchange ActiveSync issue auto redirection

[M. Sheeraz Ansari.]

Hi Tech Community,

I recently setup Exchange Hybrid with on-premises Exchange 2013 with CU23 for a customer. Customer has on-premises Active Directory as abc.local and two primary SMTP domains as abc.com and xyz.com.

Email flow, mailbox move and rest of the things look pretty good but for users having SMTP abc.com can't get their mobile app auto redirected to Office 365 URL..... meaning, as soon as we move users to office 365 their mobile devices stop receiving emails while users who are using xyz.com domain they are not facing this issue regardless of Android or iOS device. Please note, these mobile devices are on latest OS and using native app and Microsoft Outlook app.

During troubleshooting, we found out that Exchange Target OWA URL which was setup by Hybrid Wizard is appearing as: http://oultook.office.com/xyz.com

Please suggest, what could be the issue? Thanks.

[#2]

My first hunch would be DNS - I'd suggest having a look at the autodiscover.abc.com DNS record to see if that resolves to your Exchange server and then seeing if you have an autodiscover.xyz.com DNS record in place. It may be a A record if you have autodiscover.xyz.com on your Exchange server certificate or an SRV record if you don't. Also worth checking out if you have any autodiscover entries in an internal DNS zone if you are using split DNS.

Certainly worth running the ActiveSync and DNS tests from the connectivity analyser: https://testconnectivity.microsoft.com/tests/o365 to see if it kicks up any useful information.

Also worth identifying if there is any issues with new profiles on the mobile devices and/or connectivity with Outlook. You may find with ActiveSync that the credentials have been specified as domain\username rather than firstname.lastname@xyz.com which Office 365 would require to connect. In which case either update the credentials in the correct format or possibly easier for users - delete and recreate the profile.

[#3 · Accepted solution]

Thanks for your suggestion, Well, it turns out to be "Default Email address policy" issue. What we observed - as soon as user is migrated to Exchange Online, on-premises user mailbox gets converted to "mail enabled user" …….. due to this, it was getting additional non-routable proxy address as Primary SMTP which was "abc.local"

Interestingly that default policy was not applied but in the background, it was getting applied. Following is reference article that may help someone. Thanks.

Reference link: https://msexperttalk.com/incorrect-email-address-applied-after-mailbox-migrated-to-office-365/