Same issue here. I have purchased my own Nitrado server for me and a couple friends. I have the IP, entered it into Steam: went to steam library > view (top left) > game servers > favorites > add new server, entered the IP, and tells me that no server can be found at that address. Kinda sucks, but I'm a hardcore ARK lover so we just made non-ded work for now, and I can transfer the data to the Nitrado once it works. If anyone has this issue as well or has the fix/news on it, please message me.