Need multiplayer help with Steam version.
 

Bought this on the holiday Steam sale. Has been fun playing. Got 11 hours in it and have run all the tracks.
Now am looking for some online fun.
Can't join or create online game, just says check network settings.
All my other games work online even the non - Steam ones.
Also Steam gave me a key witch I haven't been prompted to use????
Any info appreciated.
Others post your thoughts.
Thanks.