Server problem

I am hosting my server on my internet, port forwarded it and everything.
Now I have had players on it at first, like friends and what not but a problem occured where at one stage my friends would start crashing whenever they joined.
I’m not sure what the problem is but I have tried to remove addons here and there to try and detect if any of them were the problem but…nothing.

There is however one person that can join my server, which is a friend and possibly the select few.
I have a sibling who also tried to join locally but still crashed and had the same problem.
All my other friends try to connect and crash at sending client info.
I’m stuck at the moment.

[editline]29th October 2017[/editline]

edit; I think I’ve solved the problem. one of the addons were outdated.