What I have had to do (without router port settings adjustments) is exit the game client, open your default internet browser and have it on a blank page (default:blank in the address bar will work) in the background as you start the game client again. Get logged in and hit your Trading Post key (default O) and ALLOW IT TO LOAD ALL THE WAY BEFORE SWITCHING TO ANOTHER SECTION OF THE TRADING POST! It works for me, I can only hope it works for you.