This error message usually means that your account has not been configured correctly. Typically this is caused by wrong file permissions (CHMOD) or invalid .htaccess commands. Depending on the server, directories should be set to 755 or 750 and files to 644 or 640. You can modify the file permissions with your FTP client.

Note that "Web Home" does not include the Apache module mod_rewrite which is required to use search engine-friendly URLs in Contao. If you still activate the Contao .htaccess.default file, it will lead to an Internal Server Error.