My Wifi-extenders RE605X and RE600X appear offline on both the router configuration page and Tether app. That does not change despite reboot of the router.

@Joseph-TP thanks! I am not able to unbind it, as it was not bound to my TP-Link account.

I once bought the wifi extender RE705X and had to return it due to the massive instability of the Wi-Fi connection. Ever since then, it remains visible on my devices list of the Tether app. Is there...