EX6100 Wifi Range Extender - Won't extend my internet connection after initial setup

The main issue - Can connect to the extender, but the extender won't provide a internett connection.

I've tried connecting with my laptop and my Sony Xperia, neither devices gets a connection. I'm using Windows 8.1.
I've used the extender successfully for about 1 month, before I changed internet vendor.
I have no issues connecting directly to the modem, but need the extender for a specific part of the house.
Everything I do here is via a wireless connection.
The extender is placed in the same room as the internet source. I've tried placing it RIGHT next my my modem, on the other side of the same room, and in the next room.
Connecting via WPS don't seem to work at all.
I did get it to work once, but once I unplugged the extender to place it at a better location, it stopped working.

This is my process: (which I have repeated several times)
I start by resetting the extender to factory settings. At this point I connect to the router just fine, and the wizard jumps into my Internet browser.
The configuration process seems to go as intended, and everything seems to be in order.
After the setup is completed, I connect to the extender, and everything seems to work... for about 2 minutes.
After 2 minutes I'm still able to connect to the extender just fine, but the extender looses it's internett connection.
Both LED arrows are lit green at this point.
At this point I try to connect to the extender, but get a message that I don't have a connection (even though I'm connected to the extender).
I try using all my 3 different web browsers (Explorer, Chrome and Firefox). And I've deleted ALL temporary internet files and such (to the point where It's as if I had just reset the whole computer from factory settings).
I have tried differenct frequencies (1,6 and 12).