If the error has been reported for your Exchange server, it indicates that the Exchange server backup files may be corrupt. ...

If the error has been reported for your Exchange server, it indicates that the Exchange server backup files may be corrupt. Follow these steps to resolve the issue:- 
1. Consult the Exchange server administrator to verify if the databases and logs on the Exchange server are in a good state. 
2. If the database and logs on the Exchange server are not corrupt, you need to run a synchronization with consistency check for this data source. 
3. In case the database and logs on the Exchange server are corrupt, you can choose to recover the Exchange data from the last known good backup.