No mailbox with such guid errors


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?

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.…

Please check the link below