Mental file backup on Windows doesn't finish

I’ve been using UrBackup for well over a year. I had my problems sometimes and it had recently destroyed a Debian system with the Linux client software, but my problem is that if I want to run an incremental file backup on my main Windows 11 computer or it should be carried out automatically.

Why doesn’t it work properly anymore? I use a 2.5G connection for backups between my computer and my server, which is only connected to each other.
My computer’s IP: 159.254.100.2
My server’s IP: 159.254.100.4

And I use TrueNas Scale as server OS and run UrBackup as Docker cage if I understand correctly.

The Log was this:

Warnings 14.08.23 22:00 Error retrieving last image backup. Doing full image backup instead.
Warnings 14.08.23 22:05 Received unknown block number: -7431704952215605851 (max: 488378112). Retrying…
Warnings 14.08.23 22:05 Checksum for image block wrong. Retrying…
Warnings 14.08.23 22:11 Received unknown block number: 4204666966030569784 (max: 488378112). Retrying…
Warnings 14.08.23 22:11 Checksum for image block wrong. Retrying…
Warnings 14.08.23 22:12 Received unknown block number: -9104125197231332661 (max: 488378112). Retrying…
Warnings 14.08.23 22:12 Checksum for image block wrong. Retrying…
Warnings 14.08.23 22:16 Received unknown block number: 2224020277743712623 (max: 488378112). Retrying…
Warnings 14.08.23 22:16 Checksum for image block wrong. Retrying…
Warnings 14.08.23 22:22 Received unknown block number: -2873200773155620008 (max: 488378112). Retrying…
Warnings 14.08.23 22:22 Checksum for image block wrong. Retrying…
Errors 14.08.23 22:51 Received unknown block number: 1431089148462567978 (max: 488378112). Stopping backup.
Errors 14.08.23 22:51 Backup failed

ok update:
I again just reinstalled UrBackup on my Windows machine and after accepting on the server that it’s the same device, image backups of both types seem to work. Why does the program have such petty quirks that aren’t fundamentally bad, but can become exhausting?

And I only specified the IP in the network, no longer that of the 2.5G direct connection, but since it can find the Windows machine both via the device name and the IP, it seems to be using both connections, for whatever reason.

What do you mean by that? Are you talking about a DMZ with your router or something?