Hello tip link team my extender network not connected please help me?

I have a Play BOX NET FTTH router. I can't change it because it's a device provided by my internet provider. I tried boosting its signal using a TP-Link RE700X. Creating an extended network in the app

My link extender started flashing all lights, briefly having the power solid and nothing else, then power flashes, and looping that pattern. I moved it into the same room as the router and no change.

No puedo conectar mi extensor de wifi luego de haber cambiado la contraseña de la red. El router no tiene tecla WPS y el extensor queda titilando(intermitente) la luz al llegar a RE. Aparece en la red

Hi, just wanting to know how to turn off dect on this device? Haven't bought it yet! Thanks.

I HAVE FORGOT USERNAME AND PASSWORD SO I TO GET RECOVER AND CHANGE BOTH