A friend of mine is currently having the same issue. Everything is port forwarded correctly and the firewall is set to allow and incoming connections (both TCP and UDP) to access the server port.
Edit: From what I have read, it has to do with the connection between the client and the server, but looking into that I can't seem to find a solution. If anybody has any insight whatsoever I would appreciate the information and if I solve the issue I will follow up.
P.S. I love how thiiaguiin13 didn't stay on topic for the thread at all and used this thread to post his issue instead of creating a new one like he is supposed to