Hello,
Neither our theme nor the plugins are the reason of the issue. You can easily check it by disabling all the plugins and switch to the default WP theme Storefront and go to Appearance > Customizer, you’ll get the error with styles https://gyazo.com/12fec68dd42cf8c79651063a7ec23907 Something is wrong with your WP installation or with your server settings. Ask your hosting provider to fix this. Our support is able to help only in case issue caused by our theme or plugin. We can’t help if the default WP installation does not work as it should.
Regards