As you can see in the previous post you replied (topic), the theme works fine in an online hosting. It does also in localhost, as we tested with MAMP and XAMPP.
Where are you hosting this? Can you please give more specifications on server status and PHP installed in it?
It seems that the customizer is not loading because of an Internal Server Error. If the issue is related to the Server is not the fault of the theme. Please see This Screenshot.
We suggest to contact your hosting provider and let us know if you have further problems.
