Contact TP-Link support and ask them what you should do.

@jeffd2651- Here's the page you're looking for. And there is a new version for your device - here.

@GamepadGL What is your link speed on 2.4GHz band - you can use this reference to determine. Try these settings for 2.4 GHz band: Have you tested with another device ?

Your internet service provider.

It may have been resolved in the latest FW that I've pointed you to, so update it and test again.

@MMessaoud It might be better to troubleshoot this with your ISP. Refer to your ADSL modem manual especially chapter 1.2.1 LED Explanation. When ADSL led is blinking that means "ADSL synchronization...