Hello Roger Blair,
Thanks for reaching out here in the Microsoft Answers Community.
Error 0x80070005 is a generic error code for "access denied". The error code alone does not tell you what caused the issue.
Since the issue happens with the Microsoft Store, you can press Windows+R and enter "wsreset" to fix certain common issues.
If the issue persists, try using another network (like broadband, smartphone tethering/hotspot, different ISPs), and try again.
If the issue still persists, we need to check with a new user profile by creating a local administrator account.
To do so, right-click Start->Terminal/PowerShell/Command prompt (Admin), and enter the following commands:
net user user1 pass1 /add
net localgroup administrators user1 /add
(Substitute "user1" and "pass1" with the username and password of the new user.)
After creating the user, reboot the computer, select the new user, and log in. See whether the issue persists.
We look forward to your response.
Best Regards,
Sheng G. - MSFT | Microsoft Community Support Specialist