I keep timing out when I'm trying to join my friends server

Me and my friend have done Gmod for at least 300 hours before this problem arose. One day I tried joining but it kept saying “Nikonov Astapkovich” has timed out. Now I went into windows and unblocked and potential firewalls and I reset my router and wiped clean gmod and everything. I started fresh and did everything, but yet it still persists. I have all the same content as him and we update SVNs simultaneously. My friend also did everything I did and he even did an O.S. wipe. What could possibly be wrong other than steam or gmod being hateful toward me?

Are you on a public server or is it one that you or your friend is hosting from home

My friend is hosting it but other people can join easy.

Please can anyone help with this because it is happening more than frequently it happens 8 out of the 10 times I try to join.

Open your ports.

I did I’ve done all that, it ridiculous