Invalid address on App Store.

I'm unable to purchase from the App Store. Every time I click on a free item to get. It first asks for Touch ID which it would recognise. Then says Invalid Address, tap continue to sign in. After I put in my password, takes me to the billing page. My credit card is selected as None. I click Done and it says your app will begin to download now. But nothing happens.

I have done this a thousand times. Please help.