@Inul_ae TL-WR720n router is with an "End Of Life" status long time ago (it's lates FW release is from 2016) and most probably that's the reason tether app no supporting it.

@121w2f Make sure your router transmits on a wireless channel that archer t2e can see, i.e. changing wireless channel to 36 (for example).

@KamiFrost Setting DNS manually for your wired client ethernet connection means that you didn't received a proper DNS information from your main router. For accessing the C80 WebGUI there are two...

@KamiFrost By design WDS should allow you to use the ethernet ports of the extended router (C80 in your case). I've seen similar reports regarding LAN ports of the extended router and that's an...

@caltr4 If you see the option "Forgot password ?" you can try to start a password recovery procedure. If you bound your TP-Link ID with your device, you can try login with your TP-Link ID account. In...

@MSM12 Check this video for how to setup a RE in a mesh.