The following errors is returned during a mailbox migration:
The specified object was not found in the store., The process failed to get the correct properties.
ErrorCode = ErrorItemNotFound
OR
Could not save: "An internal server error occurred. The operation failed., The process failed to get the correct properties."
It can happen when someone deletes items from the target mailbox after a successful migration, but modify it later in the source mailbox. (e.g if you add emoticon to the message like thumbs up or so..) Please note that not only deletion can be the cause of this, it is also possible that the target mail cannot be opened / accessed.
During the new migration which ideally runs in Mail Sync mode we will detect that the source item has been updated, but the target mail cannot be updated, and the above error is thrown.
The difference between the first and second errors from aboe is that the exception from the second error is also triggering the outer "An internal server error" exception.
It is strongly suggested not to make direct changes to the target mailbox while migrations are on-going. In the event changes are necessary and incremental migrations are planned, you should ensure items are in their original location in the target mailbox. Items that have been deleted should be restored to avoid errors being returned during a mailsync migration. In the event items have been removed and cannot be restored, refer to the user guide on running a new non mailsync migration task to re-migrate deleted items.
You can also download and check the migration report for the mailbox under the Reports tab in your Accounts project to get more information which items failed the migration.
