It could be a problem with the Microsoft servers. The following threads were created on December 2 or 3.
Windows Store not updating any apps. - Microsoft Community:
https://answers.microsoft.com/en-us/windows/forum/all/windows-store-not-updating-any-apps/050f89c5-6914-4eb3-a067-41941df88694
Windows Store won't update - Microsoft Community:
https://answers.microsoft.com/en-us/windows/forum/all/windows-store-wont-update/2e18c601-5d5b-469d-8efb-0432259a8f23
How am I suppose to update Microsoft Store if it wont update through - Microsoft Community:
https://answers.microsoft.com/en-us/windows/forum/all/how-am-i-suppose-to-update-microsoft-store-if-it/853b61ee-b24d-42f0-b749-7c03ff1eca0a
Microsoft Store gets stuck while updating... - Microsoft Community:
https://answers.microsoft.com/en-us/windows/forum/all/microsoft-store-gets-stuck-while-updating/863ea8a0-120c-4a5c-8e35-e0c3bc74e97a
How can I fix my microsoft store app. - Microsoft Community:
https://answers.microsoft.com/en-us/windows/forum/all/how-can-i-fix-my-microsoft-store-app/b0d6afe2-5b95-42f1-b895-2843aafdd323
Microsoft store just won't work - Microsoft Community:
https://answers.microsoft.com/en-us/windows/forum/all/microsoft-store-just-wont-work/1306aadd-f37c-41b8-85a2-89dfb89036b5
I can not update or download some applications on Microsoft Store - Microsoft Community:
https://answers.microsoft.com/en-us/windows/forum/all/i-can-not-update-or-download-some-applications-on/ecfc6549-2bb5-4f15-8a4a-0f01ea64dbe0
You may wait for a day or so. If the issue is unresolved, send your feedback to Microsoft via the Feedback Hub (Win+F)