Image backups fail - Connection to client broke

I didn’t see any other posts that were really related, I apologize if this is a duplicate post.

Last week image backups were working properly, so I’m not entirely sure what’s happening - the only change I made was I installed a UPS so everything had to be shut down.

Both incremental and full image backups are no longer working at least for LAN clients. The backup starts to index then fails stating the connection to client broke.

This is the only line on both the server and client logs.

Exchanging data with client during image backup preparation failed. Connection to client broke.

I have just initiated a remote incremental image backup to see if it’s an issue on my LAN side or not (which would be really odd).

Update
Remote image backups seem to be working fine.

Server is running on docker on a Synology NAS, latest version - UrBackup 2.4.13
Clients are all running latest Windows version

The issue one my PC seems to have resolved itself after restarting the server, but my laptop is still having the same issue even after rebooting the host.

The image backup resumed successfully, but then the backup itself failed again.

Report:
( 3 infos, 0 warnings, 2 errors)

2021-03-19 13:46:44(info): Starting scheduled incremental image backup of volume “C:”…
2021-03-19 13:47:28(info): Basing image backup on last full image backup
2021-03-19 13:49:28(error): Exchanging data with client during image backup preparation failed. Connection to client broke.
2021-03-19 13:49:28(info): Time taken for backing up client : 2m 44s
2021-03-19 13:49:28(error): Backup failed