What's wrong with the online in this game?

On any given build server, All of the other player’s buildings and contraptions always appear as the big red ERROR model. What’s up? Am I doing something wrong here?

You don’t have certain models or a game, like on some servers you need to have CSS or TF2 ect.

You should install PHX and WIRE. Alot of people and servers use those mods to build stuff.

PHX contains all kinds of handy building props which many use and wire allows script kiddies to make “computer like creations” (Stuff that kills/scares/annoys other players.)

You probably don’t have the Phoenix Storms 3 pack, which most servers use these days.