Contact form 7 not working correctly

Hi have you any idea why my contact form 7 plugin isn’t working properly. I’m using pagebuilder & contact form 7 and Vantage theme and I’ve used this on lots of other websites and never had the problem before.
I’ve just set up a new website and when I submit a test on the contact form, it isn’t showing up the ‘confirmation that the message was sent’ & it shows a ‘timer’ so it looks like it hasn’t submitted, but I do actually receive the details.
I’m not using any other new plugins that I didn’t use on other websites so I don’t see how it could be a plugin confliction.

URL: http://www.onthebeachproductions.co.uk/contact/