Need Some Internet Connection Wizards Help.

Alright so I was finally able to find out why it was tough for me to get into TF games and my "Lost Connection To Server/ Connection To Server Timed Out" pop ups. I unplugged the router in my rooms internet ethernet cable and basically plugged the internet cable directlly into my PC. After doing so the game connects flawlessly. After switching back to how it was before (connecting the internet back into router) the issues were back again. Thus I can say it has somthing to do with my D-Link DI-604UP router.

Now my question is what could be the possible reason with the router that causes it to mess up my connection to TF? Im not to smart when it comes to internet connections so can anyone help me?