absol77 tbh I'm still trying to configure mine as well. Well I'd advise you to get in touch witht their staff. If I have any luck I'll let you know but it's pretty annoying that others can host their servers online while I can't considering the ping being always in the 200s which is pretty high. Such a good game but support is tough.

absol77 I'd advise you to check your dedicated.cfg files. There's a youtube Vid which helps setup a zombie server but the process should be the same for mp.
Here's the link https://www.youtube.com/watch?v=5M7hz-ZnTiQ&t=1178s