Recently, I've been having an issue with my game. Everytime i join a server, any server , I keep getting timed out for 5 seconds or so every 2-3 mins. Previously , I didnt have this problem at all. It only appeared 2-3 days ago. I was having an issue with my Internet. I know my internet is working since all my other applications are working fine and its only TF2.
My internet is a LAN cable that's connected to a range extender(AC750 Wi-Fi Range Extender).
I think it might have something to do with ports or stuff which Im not too familiar with. :(

Solutions I've tried so far :
Turn off steam cloud synchronization. (It makes it worse)
Verified game cache. (no diff)