Error: User Not Authorized

The Solution #S

I believe I have found the solution (it worked for me). You need to change the device language to "English (United States)" from the settings menu on your phone (if yours is already set to United States, you can try choosing a different country). After changing the language, when you enter the game, the prices will appear and you will be able to make purchases (if it doesn’t work, you can try restarting your device).

I suspect this issue is due to restrictions between countries, which is why purchases fail in certain regions.