Plugin fails to display e-mail pop up window

Dear support,

Our plugin fails to display the e-mail request window after an item has been added to the cart. No action happens instead.

Ideas on how to fix this would be welcome,

wp-admin and ftp login credentials can be found here https://villatheme.com/supports/topic/plugin-crashes-our-site/

Thank you,

Kind Regards,

Pairfum London