Multiple Form Submissions

The contact 7 form is creating multiple submission requests and sending the client multiple emails.

I tested the form and it only sent one email.

Is it possible this is user error or a plugin conflict?

Here are the submission times from one guest:

2020-12-14 20:39:38
2020-12-14 20:31:47
2020-12-14 20:31:20
2020-12-14 20:31:01
2020-12-14 20:30:37
2020-12-14 20:30:27
2020-12-14 20:30:06
2020-12-14 20:29:52

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