After upgrade to the new version of Veeam Backup and Replication (9.5) you could get a failure within your Microsoft Exchange Backups.
The Backup runs even normal and ends apparently successful. But the logs are not being truncated and the event logs might shows an event ID 2034.
Veeam confirms that this is a known issue KB2191. The failure comes if you disable the log truncation for Microsoft SQL in the job properties. If you enable SQL log truncation even if there is no SQL in this job everything works as expected.
Exchange log truncation is regulated by a WinAPI (SetBackupSucceeded). This is a boolean value and must be set to true to cleanup the logs after Exchange Backup. If you don’t activate SQL log truncation this value is set to false and no cleanup will be done in Exchange…
Because it is a known issue I think it will be fixed in the next update. Until it is fixed you have to enable SQL log truncation to get Exchange logs truncated.