Cannot log in after importing

Problem Description

After importing a zip from Manage->Server Settings->Import, the login screen loses the background image and the login button and links are locked.

HAR trace shows 403 errors in loading of UI components, and CSRF errors in the console tab of the browser developer debug panel.

Solution

There might be other causes.  Check this one first.

If you are using HTTPS at the time, try HTTP and see if  you can log in.   If so, check server attributes.  The import operation may have cleared your domain whitelist.