Backup not created via Veeam, how to find the reason?

Question

linux

there are two virtual machines with debian 10 on Hyper-V, and an external usb drive. in one of them a hard drive is mounted, Samba is configured, and a network shared folder, 1TB in size, is occupied by about 700GB. I'm trying to create a backup on a removable disk, 1 TB is enough space. The process lasted more than a day, but 0% was still completed. Switched a removable drive to another machine, mounted a network drive. and nfv I try to create a backup of several folders, everything turned out pretty quickly. I selected all the folders, but the process did not go, it's been 14 hours.
I see these lines in the log:

log

[07.05.2021 21:15:03.869] <140277216487168> lpbcore| Initializing CBT indices. ok.
[07.05.2021 21:15:03.869] <140277216487168> lpbcore| The following snapshot storage files should be excluded from backup
[07.05.2021 21:15:03.893] <140277216487168> vmb | Backup compression level: [Lz4].
[07.05.2021 21:15:03.893] <140277216487168> vmb | [3afc] >> : setTrafficCompressionLevel\n5
[07.05.2021 21:15:03.893] <140277216487168> vmb | [3afc] out:
[07.05.2021 21:15:03.894] <140277216487168> lpbcore| Performing file-level backup: [/mnt/uatiS1/UATI].
[07.05.2021 21:15:03.894] <140277216487168> vmb | [SessionLog][processing] Backing up files /mnt/uatiS1/UATI.
[07.05.2021 21:15:04.123] <140277216487168> lpbdeve| ERR |Failed to create DeviceInfoEx for device [/dev/sr0].
[07.05.2021 21:15:04.123] <140277216487168> lpbdeve| >> |Носитель не найден
[07.05.2021 21:15:04.123] <140277216487168> lpbdeve| >> |Failed to probe device [/dev/sr0].
[07.05.2021 21:15:04.123] <140277216487168> lpbdeve| >> |--tr:CRealBlkidAccessor: Failed to probe device [/dev/sr0].

but there is - Agent.Target.log
and there is
[05/07/2021 21:35:06.414] <140609411962624> cli | WARN|MTA invoke thread : timed out for backup events. Wait cycle will be resumed for '336' hours.
[05/07/2021 21:35:17.134] <140608438007552> cli | WARN|MTA invoke thread : timed out for backup events. Wait cycle will be resumed for '336' hours.
[05/07/2021 21:35:17.147] <140608412829440> cli | WARN|MTA invoke thread : timed out for backup events. Wait cycle will be resumed for '336' hours.
[05/07/2021 21:35:17.282] <140608261826304> cli | WARN|MTA invoke thread : timed out for backup events. Wait cycle will be resumed for '336' hours.
[05/07/2021 22:15:01.972] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/07/2021 23:15:02.178] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 00:15:02.206] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 01:15:02.251] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 02:15:02.276] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 03:15:02.317] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 04:15:02.338] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 05:15:02.368] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 06:15:02.423] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 07:15:02.466] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 08:15:02.507] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 09:15:02.549] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 10:15:02.589] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.
[05/08/2021 11:15:02.639] <140609437140736> srv | There was no finalized server sessions during the last 60 minutes.

Answer 1

So what prevented you from googling the error?
https://www.google.com/search?q=veeam+Failed+to+pr...
lsmod |grep veeam what does it show?