Are you the client or are you attempting to host the server ?
Do you have TCP and UDP port forwarding rules setup in the router ?
Have you verified the functioning of the server on the LAN?
Do you have a static IP address on the PC hosting the server?
If you don't know where to find the WAN address on your router, then you can't be sure that "xxx.xxx.xxx.xxx" is your public IP address. You could have an ISP double NAT situation or something happening. You need to validate the WAN address of the TP Link."xx.xxx.xxx.xxx" is my public ip address, and im not sure where to find the WAN address