customize.php Not working

customize.php is not working what will be the issues?

Navigation : Appearance>> Customize

The smaple.com page isn’t working

smaple.com is currently unable to handle this request.
HTTP ERROR 500

Hi @seoshiv,

Sorry to hear of the problem you are having.

I have tested it on my test site and it’s working fine for me using latest version of Sparkling theme.

Have you made any changes in the theme files or using child theme?

This can be due to plugin conflict on your site so please try temporary deactivating all plugins and see whether everything works fine and then enable the plugins one by one to see which plugin is conflicting if any.

Best Regards,
Movin