Quite a few of our customers said the form is either not loading or it says the form is from an insecure source. https://www.mudpieseducation.com/ Our form is under "book a free trial online"
When I click on your book a free trial online button it takes me to a form on HubSpot's https://share.hsforms.com/ domain, which loads correctly for me and everything shows as secure. Sometimes ad blockers can prevent forms loading for site visitors, but that shouldn't be the case on https://share.hsforms.com/.
Is it possible to get a screenshot of the page with loading issues and any errors shown?