Go with FTP or SFTP to “YourWEBSite”/wp-content/plugins/header-footer-elementor/ and Edit the PHP File “header-footer-elementor.php”

and

Change from

/**
* Include Composer autoloader.
*/
require_once HFE_DIR . ‘vendor/autoload.php’;

to

/**
* Include Composer autoloader.
* require_once HFE_DIR . ‘vendor/autoload.php’;
*/

Save and login normal with YourWEBSite”/wp-admin

@mlaughter As far as I know, you will have to go through FTP and edit that file, or restore the website from a backup if your host has provisions for that. If you want to edit the file, you must ask your provider for the user name and password for your FTP access.

Just for others with the same problem: Instead of using FTP, there is often also the option of going through the “File Manager” (or similar) of your website host. In that File Manager, there is usually an option to edit individual files, and then you can make the change mentioned by turheim above.

As soon as you make the change and save the file, and go to the affected website, the website will work again, and, if auto-update is enabled for the Elementor Header & Footer Builder plugin, within a few minutes it will have auto-updated the plugin again (currently to version 1.6.31). (If auto-update is not enabled for that plugin, update the plugin manually in the /wp-admin interface.)

That update will then change the edited file to a corrected version, and everything will be fine again.