Waiting for the App Store

When activating my 7 day trial for Lightroom, it keeps loading a message saying: "Waiting for the App Store".

Every once in a while, it asks me for my Apple ID password and then sends me a message saying: Your account is not valid for the Australia store, please change your region to Spain and try again. 

I bought the computer in Australia but live in Spain. have tried changing the region in the App Store but it doesn't seem to work.

Thanks