WebGL build clients cant see Windows build host

For some reason my WebGL build clients (hosted on my own site) cant seem to connect to Windows build host. This is what i get in browser's console:

WebSocket connection to 'ws://server_external_ip:port/' failed: Error in connection establishment: net::ERR_CONNECTION_TIMED_OUT

Error: undefined socket will be closed

My server writes its external ip to the database, and clients access that database and try to connect to that ip. Im using useWebSockets in client and host. I also have set up port forwarding correctly, checked it through https://portchecker.co/, and it can see the port as open when the server is running. I also tried to write my own basic javascript websocket client and tried to connect to the server, and it wont connect either, so its not a client problem. Im using basic HLAPI, StartHost on the server and StartClient on the client. Does anybody know whats the problem here?