Cannot connect to wifi range extender

I have set up the wifi range extender, initially very close in same toom as the router. Everything lit up green.

I then moved it to the floor between the router and laptop I need the range extending/boosting to. The lights Router Link LED is green, and are the power and WPS LEDs.

This is a small 3 floor wood frame building. The router is on the ground floor, range extender on the middle fllor (directly vertically above the router), and my laptop on the top floor. I already have poor wifi on the top floor but bought the extender to increase the strength of the signal. The router is pushing c.70Mbs, but I only get c.5Mbs on the top floor.

When I try to connect to the 2GEXT or 5GEXT I am told my network password is incorrect, but I have typed it in correctly multiple times, and it definitely is not incorrect. I also do not use WEP network security.

The FAQ tells me that this means the range is probably border line, but it is not and all the lights are show it green, not ever yellow. This is the same when I place the extender twice as far away. 

Please let me know any advice on fixing this so I can use this product. Thank you!