Plutonium

I understand this topic has been talked about, but nothing is working. Have two open UDP ports for 28960-61 and 28963 for server. Have tried leaving the server min and max ping at 0, have tried leaving them both empty, tried using values. Still saying for low ping players only. The server is using a custom map if that makes a difference, but that mod and connecting the map wasn't an issue. I also have very stable and high speed wifi. Any help would be appreciated.