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MayBe1985's avatar
MayBe1985
Copper Contributor
Nov 13, 2021

Access old Exchage after migration to 365

Hi all So I have migrated from Exchange OnPrem to Exchange Online. Before migration I have taken a snapshot from the Exchange server, just in case. Now, there is a user who claims that some of her...
exchange online
Exchange Server
hybrid
Dan_Snape's avatar
Dan_Snape
Bronze Contributor
Nov 16, 2021

This is probably occurring because the account you are using has the targetaddress attribute pointing to EXO. I don't have any answers on how you get around that though. Depending on how mail is flowing and where autodiscover is pointing, the targetaddress attribute may be critical

  • MayBe1985's avatar
    MayBe1985
    Copper Contributor
    Nov 17, 2021

    Dan_Snape 
    Thanks for your reply

    Do you at least have the information of the flow?

    Say, first it checks DNS for the autodiscover, then it checks the autodiscover and checks to which server it points, then it looks at xyz etc.

    If you know the answer it would also be helpful to hear what happens if it doesn't find the autodiscover or any other file along the way?

    I do want to point out again that I attempted to login straight via the OWA on the (copy of the) Exchange Server itself, using "localhost" as the url. This server is supposed to be unaware of the migration, as it is a snapshot from before. So it doesn't really make sense to me that it would be looking for an autodiscover, which is used by a email-client to locate the server. The only thing it sould be checking is the username and password, which it is supposed to get from the DC

    Thanks again for trying

    • Dan_Snape's avatar
      Dan_Snape
      Bronze Contributor
      Nov 17, 2021

      If mail is flowing via the on prem Exchange (including anything being relayed), messages will be redirected as per the targetaddress attribute. This is the same for autodiscover. If mail is flowing directly to EXO, no on-premises apps or devices are relaying via on-premises Exchange, and autodiscover is pointing to EXO, then it's not a critical attribute.

       

      For your access to the EAC, the OWA/ECP will check the value of the targetaddress attribute on the user AD object and redirect according to that value.

      • MayBe1985's avatar
        MayBe1985
        Copper Contributor
        Nov 22, 2021
        Wow, thanks so much for that
        when changing the info of the targetaddress atribute in AD I managed logging into the local OWA of the old exchange server
        however now I get a different error
        We couldn't find a mailbox for this recipient. Either they don't have a mailbox or don't have a license assigned
        Any thought on this, as this is the server as it was before migration there definitely is a mailbox? Where would it look for a license?

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