These are known issues with Microsoft Windows Store. Sometime, the download or update process could be pending for a long time and occasionally, players may get errors when trying to open Microsoft Windows Store. Depending on which OS version is running on your device, the solution could be different. 

The following are the solutions that helped players on Windows 10:      

The following are the solutions that have helped many players on Windows Phone

Solution 1:
'Seems like an old post but this issue still happens to me once a while. The solution is very simple, change your region settings to some other country then Restart, then change back to your own country and restart. Voila, everything should be fine now.'

Solution 2: 
Connect to another network, for example from Wi-Fi to 3G or from 3G to Wi-Fi, or preferably another Wi-Fi network, and see if the issue persists.

Solution 3:     
Check whether you have other pending apps that are big and blocking the download. Pause their downloads to allow the game download finish first.

Solution 4: 
Check on your device that date and time are correct (you can find all this in Settings). If the date and time are set to automatic, try to disable this and to set it up manually.

Solution 5: 
'I've just had the same problem. Go to settings & into messages & your Microsoft account, if it says attention required it means you have to verify your Microsoft account via email. They send an email for you to verify, if not sorry that's what worked for me.'

Solution 6:  
Restart your device and then reinstall the game. Make sure to register your account with an email first before reinstalling the game. 

Final Resort: 
Please note that the app download and upgrade process in the store are controlled by Microsoft (we do not have access to their system or your account information), so if none of the above solutions work for you, the final resort to get this sorted is to get in touch with the Store support. Therefore, I am redirecting you to the  Microsoft Support.