Your Connection is not private

Hi everyone,
If any of you know much about woo commerce then I would be grateful if you could help me. I am in the middle of setting up a website https://www.warwickshireflightexperience.co.uk, and whenever I visit the checkout page on Chrome or IE it flags up the “Connection is not private error”. The one with the big red padlock. Funnily enough it works great on Safari. Just not on the other programmes.

Do any of you have an suggestions.

Thanks in advance.