My clients are experiencing problems not being able to submit the form

Some clients have also experienced problems not being able to submit the form, as well as some people experiencing problems sending the form using a mobile. 

The form is embedded as an iframe in your website. I don't see any issues with it, both on the desktop and mobile devices (checked with iOS 11 and Android 6).

Do you know if your clients are getting some sort of an error in the form after clicking the submit button? Or something that says Please wait... in the button and then hangs up from there? 

As for the issue on a mobile device(s), is this related to the form design/responsiveness? Or is it related to the submit button not visible on mobile devices? Please let us know.