Server crashes when client joins

Hi,

I have had this problem before with myself but now it has spread to someone else.
One of my friends attempted to join the server and it crashed, he now rejoins, and as soon as it gets to sending client info it crashes. This has happened to me before and the solution
was just to wipe the server and my gmod. However he has already wiped his gmod and i’m not too keen on wiping the server again. There are no error logs in the server console when he joins, it only crashes right after he does.

Anyone have any idea whats causing it?