I'm pretty sure my music mod is not the problem, try removing client mods
Yeah, his other console logs shows the "Authentication Failed" on other places.
One after loading the new duplicator:
Activating package: NewDuplicator_Server_Final
Authentication Failed for Tyke [L] (local).
The other after making a Steam lobby:
Steam Lobby Created: 109775242714295844
Steam Lobby Joined: 109775242714295844
lobby enter torquescript callback, yourlobby: 1
this is our lobby
have a server connection!
Authentication Failed for Tyke [L] (local).
Does it crash when you host a server without any addons?