A similar fix here related to QNAS TS-251. As @FreeLink posted lets hope that's informative for TP-Link Tech Support troubleshooting purposes.

@Gerbil Check this story - it's about pretty much the same configuration as yours. From BT can confirm if you have to use PPPoE or PPPoA - I would bet on PPPoE. You may test your BT credentials and...

@JM98 The only option you have in that regard is in your device user guide - Chapter 8.4. and 8.4.1, but for that purpose you'll have to use a 3G/4G USB modem. To be able to switch between BT DSL and...

@Fahl There are two ways: 1.Using QuickConnect 2.Using EZ-Internet - this one involves port forwarding on your router. Here's the resource explaining how to do that:...

@Stiols Are these devices with the same FW and HW version ? If not update the FW and test. HW version is on the bottom sticker. I would assume that they are fine because of the fact that when on the...

@Stiols When in AP mode you don't need a remote access enabled, because the devices are in the same subnet with the router - 192.168.1.0/24. Here's the difference with router mode.