Issues with incremental Image Backups

Hello,

we have problems with the urbackup client. A full image backup is possible without problems, but the incremental backup does not work. The backup always aborts exactly after 2minutes and 2 seconds.

The clients are running Windows Server 2022 the server is the latest Docker Image 2.5.27 running on Linux.

We currently do not see firewall and network issues as the full backup works without any problems.
What could be the cause of the problem?

Here are the client logs:
Starting unscheduled incremental image backup of volume “C:”…
Image backup is based on the last full image backup.
Failed to exchange data with client while preparing image backup. Connection to the client interrupted.
Time needed for client backup -------: 2m 2s
Backup failed

Here are the server logs:
2022-11-29 11:24:33: Starting unscheduled incremental image backup of volume “C:”…
2022-11-29 11:24:33: Starting unscheduled full backup of volume “SYSVOL”…
2022-11-29 11:24:33: Transferred 706 bytes - Average speed: 564.8 KBit/s
2022-11-29 11:24:33: Updating statistics…
2022-11-29 11:24:33: Update image statistics…
2022-11-29 11:24:34: Starting an unscheduled full image backup of the “ESP” disk…
2022-11-29 11:24:35: Transferred 703 bytes - Average speed: 5.624 MBit/s
2022-11-29 11:24:35: Image backup based on last full image backup
2022-11-29 11:24:36: Updating file statistics…
2022-11-29 11:24:36: Updating statistics completed.
2022-11-29 11:26:36: ERROR: Failed to exchange data with client while preparing image backup. Connection to the client interrupted.
2022-11-29 11:26:36: Time required for client backup ----: 2m 2s
2022-11-29 11:26:36: ERROR: backup failed
2022-11-29 11:26:36: Updating the statistics…
2022-11-29 11:26:37: WARNING: Exponential backoff: wait at least 10h 40m before next backup

Client Debug log:
2022-11-30 15:13:58: ClientService cmd: #IJlKDCP74X7VyNhsQqr8F#2LOGDATA 1669817637 0-1669817513-Starting unscheduled incremental image backup of volume “C:”…
0-1669817515-Basing image backup on last full image backup
2-1669817636-Exchanging data with client during image backup preparation failed. Connection to client broke.
0-1669817636-Time taken for backing up client SH2604801: 2m 2s
2-1669817636-Backup failed

2022-11-30 15:13:58: rc=0 hasError=true state=0
2022-11-30 15:13:58: SERVICE_COMMANDS finished
2022-11-30 15:14:05: rc=0 hasError=true state=0
2022-11-30 15:14:05: SERVICE_COMMANDS finished
2022-11-30 15:14:12: ClientService cmd: PONG