No mailbox with such guid errors

Cloud Microsoft Office 365
1

Hi,

I started getting a lot of errors in Office 365 out of nowhere recently. Since I am using EWS to access office 365, I have accounts with impersonating rights to make it work. Since yesterday, I am getting loads of “No mailbox with such guid” errors on valid mailboxes. Since EWS is considered as a third party, support cannot do anything about it. Accounts are licensed and registered. How do I go about to fix this issue myself?

2

This error is commonly caused by an unlicensed mailbox account. Check that all of the migrating mailboxes are licensed in Office 365 first.

If a mailbox account has been assigned a license and the error persists, it is usually caused by a non-Null value in the “msExchMailboxGuid” attribute of the mailbox account.

Please refer the below link for more info and let me know how it goes.
https://help.bittitan.com/hc/en-us/articles/115008114287-No-mailbox-with-such-GUID-ErrorNonExistentM…

3

Hello
Please check the link below

4

By following the below steps you can resolve the error No Mailbox With such Guid Error easily.

Check Licensing: The “No mailbox with such guid” error often occurs when the migrating mailboxes are not licensed in Office 365. So, the first step is to ensure that all the mailboxes you’re migrating are properly licensed.

Verify User Existence: The next step in resolving the “No mailbox with such guid” error is to verify the existence of the user in your Exchange server. Make sure that the username you’re using to access the mailbox is spelled correctly.

Check Permissions: Another common cause of the “No mailbox with such guid” error is incorrect permissions. You need to ensure that you have the necessary permissions to access the mailbox.

Set Exchange GUID Property: If you’re still encountering the “No mailbox with such guid” error after checking licensing, verifying user existence, and checking permissions, you may need to set the Exchange GUID property on the mailbox. This can be done by opening the Exchange Management Shell and running the appropriate cmdlet.

Check msExchMailboxGuid Attribute: If a mailbox account has been assigned a license and you’re still seeing the “No mailbox with such guid” error, it could be due to a non-Null value in the “msExchMailboxGuid” attribute of the mailbox account.

Encountering “No mailbox with such GUID” error message? Follow these steps to fix it. Let us know in the comments if they worked for you. We’re happy to help!

5

It seems you’re encountering the “No mailbox with such guid” error in Office 365. Let’s troubleshoot this issue:

1. Check Licensing:

  • Ensure that all the mailboxes you’re accessing via EWS are properly licensed in Office 365. Sometimes, unlicensed mailboxes can cause this error¹.
  • Verify that the accounts you use for impersonation have the necessary licenses.

2. Attribute Value Check:

  • This error can also occur due to a non-Null value in the "msExchMailboxGuid" attribute of the mailbox account¹.
  • Confirm that the mailbox accounts have valid values for this attribute.

3. Recent Changes:

  • You mentioned that these accounts were working fine until recently. Consider any recent changes or updates that might have affected them.
  • If the mailboxes suddenly lost their licenses, investigate why that happened.

4. Support Channels:

  • While Microsoft support may not directly assist with third-party issues, you can still contact them for guidance.
  • Provide detailed information about the issue, including request/response traces, to help them understand the problem.

Remember, I recommend checking the licensing and attribute values first. If the issue persists, explore other suggestions above.