Problem solved. Solution and background: Agent has local lan IP address, and was behind a mikrotik router. I dst-nat-ed the TCP port 4700. In agent config file i set only the public IP address of server for "masterservers". When i run the agent with -D9 (debug mode), i saw the incoming connection rejected from "mikrotik's lan IP address"!
It is correct, because the agent saw the incoming connection come from his gateway (Mikrotik router) not from the public IP address of the server. So, i added the Mikrotik's lan address to Masterservers (in the agent's config file), and restarted the agent. And woila! Works perfectly!
So guys, i would like to big-big thank you for your help!!! 
				
			It is correct, because the agent saw the incoming connection come from his gateway (Mikrotik router) not from the public IP address of the server. So, i added the Mikrotik's lan address to Masterservers (in the agent's config file), and restarted the agent. And woila! Works perfectly!
So guys, i would like to big-big thank you for your help!!!
 
				 ), but the communication between server and agent is not working. The agent is behind a Mikrotik router, the port 4700 is dst-nat-ed to this machine (and rdp port also, and that is worked). If i try to poll agent, then nothing happened. If i try register manually agent to server, then:
), but the communication between server and agent is not working. The agent is behind a Mikrotik router, the port 4700 is dst-nat-ed to this machine (and rdp port also, and that is worked). If i try to poll agent, then nothing happened. If i try register manually agent to server, then: