Windows 10 Store app version 2015.8.3.2 was released last week. As of this update, you will experience:

Improvements in success launching the store app

  1. Fixes for download errors 0x803F7000 and 0x803F7003
  2. Elimination of incorrect “reached your device limit for installing apps and games from the Store on your Windows 10 device” message
  3. General stability improvements.


So do make sure you have updated.

Related reads:
How to re-register Windows Store apps in Windows 10 / 8
Fix: Windows Store not opening
Clear & Reset Windows Store Cache in Windows 10 / 8.1.