LFS DEDI - Guest wants to join

[[6S] RipstiE]

Hello,
So i wanted to have a little fun with my friend on own DEDI server. I have opened ports on my router and firewall too, but everytime he tries to connect, it tells him "Conection lost" or "Connection failed". When i look to dedi cmd window, everytime he wanted to join it writes there "Guest wants to join" I've asked multiple people and tried to search around the internet, but i haven't found anything that could help me.
Thanks for everyone trying to help me!