Can't loging from inside the same server network

Hello everyone, my problem is that i get agent server error " token timeout" when i try to log in from a computer inside the server network!
no problems to connect from outside the network, the ping is low and everything is good
i can connect from the server machine ofcourse
i tried src nat on my router but it doesnt help
sourace nat > dst ip "local ip of the server machine" > dst port " tried all ports"
any help please?!