How to change the RDP port correctly?

Question

RDP

Hello.
There is a dedicated ip address. Router and 3 PCs.
There is access to one PC via RDP (port 3389 is forwarded on the router).
On the second PC, the RDP port was changed to 3700 .. And forwarding is specified on the server .. The ip of this computer is specified and the port is internal and service, like 3700 .. I
use the standard Windows application "remote connection to remote desktops", I can not get any more RDP access..
What am I doing wrong?

Answer 1

did you look at the firewall?

Answer 2

Return the standard port 3389 on the second PC and forward on the router from external 3700 to internal 3389 on the ip of the second PC