0x8007042b error when adding yahoo or gmail accounts to Windows 10 Mail and Calendar app

There's a similar thread from 2015 How to solve error 0x8007042b while connecting a Google account on Windows 10? here but none of the answers worked. The manual method of adding accounts doesn't work with Calendar, which for some strange reason is bundled with the Mail app!

My current build is:

OS Name:                   Microsoft Windows 10 Pro
OS Version:                10.0.18362 N/A Build 18362

This is what I've tried so far:

1. That thread at the top of this post.

2. Created a system restore point.

3. Opened Microsoft Store → Settings → unchecked Update apps automatically so it won't automatically add the app upon the next restart. Done this prior to doing anything as Windows installs the Mail and Calendar app the first chance it gets.

4. Removed any existing accounts that were added manually to the Mail or Calendar apps.

5. Allowed windows full access to my location.

6. Signed into my Microsoft account → cleaned out all items from the screenshot below at this address https://account.microsoft.com/privacy/activity-history.

   

7. In PowerShell as admin.

   • WSReset.exe
   • Get-AppxProvisionedPackage -Online | Out-GridView -PassThru | Remove-AppxProvisionedPackage -Online and highlighted the microsoft.windowscommunicationsapps item and clicked OK to delete it.
   • wmic useraccount get name,sid which returned a formatted number beside my username: x-x-x-xx-xxxxxxxxxx-xxxxxxxxx-xxxxxxxxxx-xxxx.
8. In Registery Editor as admin.
   • Navigated to the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Appx\AppxAllUserStore\x-x-x-xx-xxxxxxxxxx-xxxxxxxxx-xxxxxxxxxx-xxxx and deleted that associated number found above.

9. With RegScanner in admin

   • Searched for entries associated with Mail and Calendar which have the PackageFamilyName name: microsoft.windowscommunicationsapps_8wekyb3d8bbwe and deleted any of them.

   • This left me with these which could not be removed. Their paths vary for:

     • Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\AppModel\StateRepository\Cache and this entry HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\BackgroundModel\EmptyHostDisallowList microsoft.windowscommunicationsapps_8wekyb3d8bbwe REG_DWORD 0x00000001 (1) 19/03/2019 04:53:42 4.

     • See screenshot below of any registry items found with the keyword search used microsoft.windowscommunicationsapps.

       

10. Restarting the PC, then adding the app back in, in the Microsoft store.

11. Still getting error 0x8007042b when I try to add either Yahoo or Google accounts to either Mail or Calendar.
12. This leads me to believe that the cache registry folder in step. #9 above is the culprit which cannot be deleted, even when I tried using Registry DeleteEx.
    • FYI, I have even user ids inside the folders here Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\AppModel\StateRepository\Cache\User which no longer exist.