x500 value is missing in mailbox post Office 365 email migration.

Gurudas 886 Reputation points

Hello Team,

Greetings for the day!

We have migrated a mailbox john.dave@Company portal .com to office 365 post which we were not able to configure Outlook profile due to X500 value missing or license is not assigned to the mailbox error.

Your quick help will be highly appreciated!

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Accepted answer
  1. Joyce Shen - MSFT 16,646 Reputation points

    Hi @Gurudas

    Yes, usually the missing of X500 address may cause message deliver issue, sender will receive a NDR when send emails to the recipients missing this value.

    Could you please share the complete error information or screenshot when configure the outlook profile? And what's the result test outlook connectivity: https://testconnectivity.microsoft.com/tests/O365Ola/input

    If you think your issue is related to missing X500 address, you could also take a reference at the links below which will help you recreate them:
    Please Note: Since the web sites are not hosted by Microsoft, the links may change without notice. Microsoft does not guarantee the accuracy of this information.

    Also, the operation to Assign Microsoft 365 licenses to users

    If an Answer is helpful, please click "Accept Answer" and upvote it.

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3 additional answers

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  1. Vasil Michev 98,281 Reputation points MVP

    Missing X500 value should not result in any issues with configuring Outlook profile, check for license and make sure autodiscover is configured properly. What method did you use to migrate the mailbox?

  2. Amit Singh 4,861 Reputation points

    Was the IMCEAX address included in the NDR? If it was, convert that value to an X.500 address.

    Here is the reference article with a script - https://www.azure365pro.com/convert-imceax-ndr-to-x500-value-with-reference-table/

    Add that value to the mailbox of the original email's recipient. This should allow the mail routing to work with the existing autocomplete values. If that doesn't work, you really do have to remove all of the auto-complete values because they won't work due to the way the migration was completed.

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  3. TClark 0 Reputation points

    We have the same issue post O365 to O365 migration. There are no NDRs produced by the user. Email functions properly. Calendar is the only effected item. Recurring meetings that were created pre-migration cannot be edited by the user in Outlook app or OWA.

    All other users migrated into the new tenant with an X500 address. This one did not.

    We have access to the old tenant and there is an X500 address on the problem user's account, but I don't want to copy/paste it since all users copied over with a different X500 address compared to their original tenant.

    I can't create a new X500 without the NDR email info, right? Any recommendations?

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