Hi there,
Checkout the below link
https://www.mhthemes.com/support/theme-customizer-not-working/
In case troubleshooting and disabling your plugins doesn’t help and if you are desperate because you also can’t find other reasons for your issue, then you could try to add the code snippet below to the file wp-config.php of your WordPress installation and it may resolve your issue.
“define(‘CONCATENATE_SCRIPTS’, false);“
If you would still like to edit your widgets without going to Customize page, then
you can use the following conventional steps as specified in the below support document.
https://codex.wordpress.org/WordPress_Widgets
Go to Appearance > Widgets in the WordPress Administration Screens.
Choose a Widget and either drag it to the sidebar where you wish it to appear, or click the widget, (select a destination sidebar if your theme has more than one) and click the Add Widget button. There might be more than one sidebar option, so begin with the first one. Once in place, WordPress automatically updates the Theme.
Preview the site. You should find that the “default” sidebar elements are now gone and only the new addition is visible.
Return to the Widgets Screen to continue adding Widgets.
To arrange the Widgets within the sidebar or Widget area, click and drag it into place.
To customize the Widget features, click the down arrow in the upper right corner to expand the Widget’s interface.
To save the Widget’s customization, click Save.
To remove the Widget, click Delete.
Hope that helps.
