Well, without access this is going to be very hard. Unfortunately screenshare is not an option for us.
Try the following:
– Make sure there is no duplicate of jQuery loaded. If you are using a customized theme, we have seen custom jQuery loaded to the site footer. This causes the previously loaded scripts to unload. Removing the duplication helps.
– Make sure that the wp_footer() call is present in the footer.php file in the theme directory. Custom themes or child themes tend to miss that and the scripts can not load.
– You can also try this option. If it helps, then the wp_footer() call is probably missing from the theme.