The Website and BattleMetrics join server links appear to be broken. Not sure when steam updated their protocol but https://developer.valvesoftware.com/wiki/Steam_browser_protocol indicates 12 September.
Using AU Scourge as an example the links point here: steam://connect/172.111.33.31:28013
But the working link should be this: steam://run/252490//+connect 172.111.33.31:28013
Server: Scourge