Bareos, falls off in the process with "ERR=Connection terminated by the other side", how to find the reason?

Question

Backup

Greetings!
I set up backups using Bareos (V17.2), everything is ok with local clients, the problem is with the remote one.
The remote ones are connected via vpn (OpenVPN), the configs of the local and almost remote ones are identical.
The task starts, in bconsole I see that the files have begun to be copied.
At different intervals, an error arrives:

bareos-dir JobId 4: Fatal error: Network error with FD during Backup: ERR=Соединение разорвано другой стороной
bareos-dir JobId 4: Fatal error: No Job status returned from FD.

and accordingly the task is marked as failed.
BUT at the same time in bconsole on status client this task is marked as OK! and, judging by the size of the backup, it was completely finished.
I checked the connection to the server during the backup - "not a single break!!!" (ping),
There is nothing else in the logs... The CPU load during the backup was minimal, as was the number of disk accesses, the system did not freeze.
How would you identify the problem?