PP Client Installation issue with Change Active Server Location

Hi all

after the download and installation of the PP Client 9.5 it asks for the server location. Entering the data given by the Server Homepage it always fails to connect correctly. Resolve host name and ping are o.k. but Server version (https) and (http) fail. This only happens when the client is started by another computer than the server. What could be the problem? Probably, some settings are wrong, but I couldn't identify them. In "Settings for Web Client Hosts" it is stated, that one can change the Authentication Method to a domain, but I see only "Any User Name" or "Local". For testing I set this option to "Any User Name" but I would prefer "domain". I also created new SSL certificates but I can't restart the server at the moment because some important and long running jobs are (still) active.

Best regards,
Lina