Using 2x EX7700 as access points to improve our home network and struggling....

Hi, we originally tried to used the 7700 as a range extender but the signal would continually drop out and we were not getting good coverage at all.

We decided to configure them as access points and have run through the process as instructed through our online account, the internet is working but we are experiencing lots of buffering and now the room with the original router in loosing signal fairly often. it keeps connecting and then drops out and forgets the password, we type it in and it forgets it again.

We have the first wifi access point connected by ethernet cable directly into our plusnet router LAN port, then we have plugged the second access point into the port at the back of the first access point. All have the same SSID and password. Anything i am doing obviously wrong? I have read a but about DCHP enabling and disabling but from what i have read it is automatically diabled in the 7700 so i should leave it enabled on my router!

Open for help! working from home and this is a cause of daily frustration!