Some Windows 10 users are failing with error 0x87AF000B during an attempt to download or update Apps from Windows store.Then it's not possible to receive apps from Store.
Searching the Internet for this error code returns several hits in Microsoft Answers (here). Using wsreset.exe to reset the Windows Store app or reset Windows Update store (see here) won't cure this issue.
My suggestion is, to create a new (local) user account, and login to this account. Then launch the store app and try to connect the app to a Microsoft account. If app downloads now possible from Windows store, then the old user profile seems to be damaged. In this case I would safe user data from this profile, delete the account and create a new account with the same name. This approach has been mentioned also within this forum thread.