Hey, I just got the local update way from tp-link support before and you may have a try. For this problem, we recommend a Local upgrade. Please have a windows computer to follow the instructions:...

Firstly, we should connect the main deco unit to your internet with a cable connection. In that case, we can put another RE unit in the room with the two devices. And connect both of them into the...

Try to hard reset the router and reconfigure it. Good luck..