Seems to crash every time in multiplayer even though they also had the mod installed

Thanks for letting me know. Do you know the specific error message?

Here is the exact error:
Error while running event player-trails::on_tick (ID 0)
player-trails/control.lua:515: attempt to index local 'player_settings' (a nil value)
stack traceback:
player-trails/control.lua:515: in function 'animate_existing_trail'
player-trails/control.lua:540: in function 'animate_existing_trails'
player-trails/control.lua:595: in function <player-trails/control.lua:588>