NetGear AC1200 WiFi Range Extender (EX6150)

I replaced my router and reset my extender so that I could connect it to the new router. I can connect ok (did via WPS) but when I try to connect a mobile device (or any device) to the extender, I get a message saying 'incorrect password'. I am using the correct password (same as my router). I used an ethernet cable to join the extender to a laptop and tried to go to the extender settings at the extender IP address. I got to the page for New Extender Set-up and entered my details but when I click 'Next" the genie doesn't let me progress - have checked for blocks but none are in place.