OpenManage cant access the catalog file in the DRM

Hi guys,

I have two seperate systems (OpenManage and DRM), but in the same subnet. I can see via tcpdump on the DRM (Ubuntu 20.04) the incoming traffic from the OpenManage, but the OpenManage says he cant access the catalog file. (iptables allow traffic and dont block it)

In the logs /syslog or /var/dell/drm/log I cant find anything that gives me a clue why it dont work.
So have you some ideas where I can start from and trying to get work.