Would you please kindly make a backup of your website and update the theme to version 1.2.6:
The new version gives a better error handling and you will get an error message showing why this is happening in your environment.
After that kindly follow the instructions below (Especially the plugin conflict and cache section):
If you still have issues kindly get back to us with the information below using the Secure Note functionality of the post:
- WordPress Dashboard URL
- WordPress Dashboard User
- WordPress Dashboard Password
- Name of the page to check