Hi Cobawski,
Thank you for buying our theme. We hope it will meet all your expectations! 🙂
My best guess is that there is an incompatibility issue between the version of some plugins. Can you please make sure the theme and all plugins are up to date?
Once you updated the theme and all plugins, we really suggest you to reset your WordPress database using WP Reset (https://wordpress.org/plugins/wp-reset/) and start fresh with our setup wizard.
You can easily install the theme by relaunching the setup wizard, as it will programmatically do every steps for you.
We’re waiting for your feedback.
Regards,