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Activesync Incorrect after migrating back to On Prem RRS feed

  • Question

  • Hi All,

    We recently migrated our mailboxes to O365, however for reasons I wont go into these need to come back on prem again before going back up to a new 365 tenant. 

    We migrated a mailbox back to our 2010 on prem server from office 365 successfully however activesync on the mobile devices are not working post migration on these test mailboxes. 

    It seems autodiscover was updated from our previous external url to outlook.office365.com during migration however on return to on prem the mobile device appears to still be looking at that for activesync rather than returning to our on prem server.

    I have run MCRA and that has been successful however whilst I am able to authorise and login to the account on the device it will not sync email and all records indicate its still trying to go to O365. 

    If I create a new mailbox and user on prem without ever going to office 365 this works fine so its something in the process of the mailbox being migrated up and then back down which is not working. 

    We have run through all mailbox attributes and ad attributes and cannot see this value set so believe it must be something server side which may have been reconfigured when the Hybrid wizard was run which now needs changing back.

    Not alot of documentation around activesync coming back on prem only mailboxes. 

    To set out the scene its 2 x exch 2010 servers running in a DAG, we have a ex 2013 box for migration to O365 but CAS has been left as 2010 as this was planned to be decomissioned. 

    Any help is appreciated.

    Lee

    Tuesday, September 22, 2020 6:28 PM

Answers

  • Hi,

    According to your information above, mailboxes migrated to o365 then moved back to on-premise not working properly with activesync, however newly created on-prem mailbox can work well.

    What's the result using ExRCA tool to test the connectivity of activesync?

    Have you tried removing the profile on your mobile device then re-create it to test the result again?

    Make sure your steps are right like the official document lists: Move mailboxes between on-premises and Exchange Online organizations in hybrid deployments

    Here is an article introduces about the process Exchange ActiveSync on-boarding to Office 365 for your reference as well.

    Please note that, this Exchange Server Development forum mainly focuses on scripting issues, And the previous TechNet Exchange forum has been migrated to Q&A forum, please post your issues there if you need further support. 

    Regards,

    Joyce Shen


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    • Marked as answer by Leedstc Thursday, October 8, 2020 8:10 AM
    Friday, September 25, 2020 6:28 AM

All replies

  • Hi,

    According to your information above, mailboxes migrated to o365 then moved back to on-premise not working properly with activesync, however newly created on-prem mailbox can work well.

    What's the result using ExRCA tool to test the connectivity of activesync?

    Have you tried removing the profile on your mobile device then re-create it to test the result again?

    Make sure your steps are right like the official document lists: Move mailboxes between on-premises and Exchange Online organizations in hybrid deployments

    Here is an article introduces about the process Exchange ActiveSync on-boarding to Office 365 for your reference as well.

    Please note that, this Exchange Server Development forum mainly focuses on scripting issues, And the previous TechNet Exchange forum has been migrated to Q&A forum, please post your issues there if you need further support. 

    Regards,

    Joyce Shen


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    • Marked as answer by Leedstc Thursday, October 8, 2020 8:10 AM
    Friday, September 25, 2020 6:28 AM
  • Hi Joyce, 

    It turned out to be our MDM solution which mobiles proxy through has a built in cache which needed clearing, once cleared it then checked in with Exchange 2010 (using autodiscover) to update the mailbox location and activesync then worked as expected.

    For continuity the MDM solution was Mobileiron incase anyone else comes across this issue.

    Thanks,

    Lee

    Thursday, October 8, 2020 8:10 AM