Race canceled problem help please !!

[ecureuilbooster]

My friend and i are renting a server on assetto corsa. I Started the server with mods i have i was able to connect. My friend keeps having «race canceled message » an other friend of our was able to connect to the server no problem. I removed 1 of the cars he had just installed to the game thinking that car was the problem and he was able to connect. We really want to play with this mod!! My question is why 2 of us are able to connect with that mod on the server and the other one keep having that « race canceled » message ? Hellpp please !