Cannot Connect to Toybox

For whatever reason I cannot connect to Toybox when playing Garrys mod. I get the following message:
“Unable to connect to server. Server may be offline or you may not connected to the internet.-102”

I’m also having some issues with connecting to my friends servers. I was told it might have something to do with port forwarding (something I don’t understand too well)

Anyone think they could help me out?