Hi manjh, Try follow the FAQ: https://www.tp-link.com/us/faq-1077.html, if it doesn't help, better to email TP-LINK support.

Hi Stuperfied, Is the Telstra Fast 5355 connected to your ISP with telephone line and get internet access? You can configure the Archer D7 as an access point, then you can use all four LAN ports,...

Hi, How do you setup the VPN? Can you post the screenshot of the page here?

If you have any Killer Wi-Fi devices, you need to disconnect them from Wi-Fi. Try with only one device connected to the tplink. Basically it points to the router. Contact tplink support to fix it.

What's that defined device? Can you access it from internal? Do you set virtual server to open port for that device, so as to access it from outside? And the firmware version?

You mean when Traffic Statistics is enabled, the router slows down? Did you run a speed test to make a comparison?