If the problem is independent of the theme, you need to contact support of WordPress, because in this case, the theme support can’t help.
About errors in our theme files, provide URL of page where errors are visible + temporary wp-admin and FTP access, then our dev team will check them.
If you do not know how to create FTP contact with your hosting provider, they will help you.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.