Page Refresh on clicking Send button in Contact Form 7

Hi there,
The contact form 7 form was working fine a few days ago but after configuring Autoptimize plugin it started showing some problems.

1) On Clicking Send button in contact form 7, it refreshes the page and loads error after refreshing page.
2) The page refresh problem won’t appear in admin mode.

The page I need help with: [log in to see the link]