SharePoint 2010 SYSTEM account does not have full control permissions

I downloaded a trial WSP package from the Internet. After installation and deployment, I unmount the package. When something happened, the system account did not have full permission to log on to the website set. You have no permission to add a list item.

Go to the management center and check the website set administrator. No problems are found.

In the management center, the system account permissions are normal. Google once found that the website set was inexplicably changed to read-only status.

Management Center ----- Application Management ---- configure quota and lock

Solution: select "Unlocked" and click "OK.