Style Customizer is not saving the changes. What should I do?

This issue is mostly caused by the server side or the WordPress installation. On the Style Customizer screen, after saving, if you check the Chrome browser's console in Developer Tools, you may see the error message like "403", "405" or "500 Internal Server Error" or some kind of AJAX stuff (or, in a very rare case, you may see nothing about the error).

I would suggest to firstly uninstall the current WordPress and theme then try the following steps:

1. Download the latest WordPress from: http://wordpress.org/download/

2. Do a fresh WordPress installation from the downloaded package. Also, make sure to enable "WP_DEBUG" (see this: http://codex.wordpress.org/Debugging_in_WordPress )

3. Install the theme with all dummy data using steps provided in the theme's documentation.

4. Test the site again.

If the issue still persists, please try it on another servers you have or contact your web hosting and send them the error message you see in the Chrome's console. They should be able to help you out especially for the "500" error code.

Another possible reason is the PHP version on your server. Make sure that your server has the up-to-date PHP version installed.