something on the js codes checks domain. main problem is the pixfort core plugin. check /essentials-multipurpose-wordpress-theme-V3.0.0-nulled\essentials-main\Plugins\pixfort-core\pixfort-core\dist and open the index.bundle.js.map file. If you read some parts you can see the security checks. Unfortunately, I can't do anything because I don't know js very well.