First thing you should do if running Unreal / Ugold out of the box is to download and install the 227 patch (currently 227i is the latest public build), it will automatically update the master server entry in advanced options to a new masterserver.
You can acquire the patch from OldUnreal -
https://www.oldunreal.com/oldunrealpatches.html
If you're using Unreal Gold, you should download 227i for Unreal Gold, the other version is for the version of Unreal which doesn't come inbuilt with the Return to Na Pali Expansion pack.
You can edit the master server field yourself, to one of the community hosted master servers which are functional. You will be able to retrieve a list of servers, but virtually all servers (apart from a small fraction) run either 227i or one of the beta indevelopment builds. If the server is vanilla I think you would be able to connect to them, but as most servers using 227 are running mods using the newer features of the 227 patch, you won't be able to join them.
It's best to just get the latest public version of 227, as it adds alot more stability and optimizations for the game mainly for modern systems or even 'almost' modern systems.
If you encounter any issues running or installing the latest 227 public build, you should ask for help on the OldUnreal forums, because the 227 development team are always eager to help.
Good luck.