@BVC That's most probably because TL-WPA7617 doeasn't support Easymesh with an ethernet backhaul - it only supports Onemesh (details).

@nicholas_lai Deco M9+ could serve as a router and probably should be able to replace the EX510 as a main router. Check that with your ISP and if it fits their service then the EX510 will be...

@Gustsax Resetting the router to its factory defauts shoud be able to let you regain back the access. To reset the router press and hold the reset button for about 10 secnds.

@Overtech_NC Disable UPnP, reboot the router and try again:

@NevaBear Usually the guest network settings can be found here:

@sajidgg7890 It's more like: 1.Create a new TP-Link ID 2.Unbind the old TP-Link ID 3.Bind the new TP-Link ID N.B. If you decide to sell the device at some point in time, you shoud unbind your TP-Link...