Proxy for openSUSE


I am new at Nexus Repository Manager OSS.

I have installed the latest version “OSS 3.37.3.-02” on Ubuntu 20.04 and it works with Proxys for Ubuntu (apt-proxy) and CentOS (yum-proxy).
But I have no idea to run it with SUSE (SLES or openSUSE). I have create a raw-proxy, followed this article:

But that doesent work for me:
Repository ‘Main Repository’ is invalid
Valid metadata not found at specified URL
Repository type can’t be determined

Any ideas?
Thanks a lot for your help,