EX7000 Extender setup

This unit has worked fine for over a year. 2 weeks ago it stopped allowing ipad pro and samsung tab s10.5 to connect. The tried a couple more tablets but same and all them connect to other networks when taken offsite. They try to connect but says failed to obtain ip address. 

Tried going through resetting router a few times but to no avail. Had back up of router from when it worked ok but this also does not work either.

My laptop with belkin dual band usb works fine.

Also I go through set up and after setting up network name and security it fails to connect and then wont allow connection and displays message below on all devices.

It not a WPA2 OR WEP issue as tried with no security and is the same.

message below

This site can’t be reached

www.mywifiext.net refused to connect.