Unable to move mailbox from on-premises to O365 in hybrid mode with EWS proxy timed out error

Introduction:

We are in the middle of migrating users to O365 from on-premises server, which is in hybrid mode. We are migrating in batches. Yesterday we tried to migrate group of users. All users were migrated successfully in that migration batch list except one user. The error message which we got as mentioned below.

This message “Error details: The request channel timed out while waiting for a reply after 00:00:00.x seconds. Increase the timed value passed to the call to request or increase the SendTimeout value on the binding” usually will come if the O365 tenant is not able to contact on-premises CAS server. Generally this will happen because of the migration endpoint associated administrator password expiry or connectivity issue between on-premises and O365 tenant. However in this scenario, all users are migrated successfully, which means the issue is not with migration endpoint associated administrator password or connectivity issue.

Cause:

We started digging into this issue. Started comparing the attributes between on-premises mailbox and synced account in O365.

In on-premises, we used the commandlet Get-Mailbox –identity “Email address” | fl

In O365 PowerShell we used Get-Recipient –Identity “Email address” | fl

Once we got the output, we compared and found the “ExchangeGUID” value is different between both the accounts.

Resolution:

We now found that “ExchangeGUID” is different in both the accounts. We planned to update the “ExchangeGUID” value in O365 account. We copied the value from on-premises. We used the following command to update the same in O365.

Set-MailUser – Identity “email address” –ExchangeGUID “GUID value”

After that we synced the account again using AD Connect. Once the sync is completed we tried to move the account and it worked as expected.

Hope this information will save your time just in case you got stuck with this issue. We are not sure why the GUID value got changed in O365. Please comment below if you have any additional information regarding this issue.

Happy troubleshooting 🙂