Customer firewalls preventing submission

we have now had 2 customers unable to submit their data because their firewall is blocking the form, how can i stop this happening? 

The thing is, the people we are dealing with very often wont even know who to talk to in order to achieve what you are suggesting. Why is jotform being blocked by security? surely the site has a security flaw if this is the case? 

Is this form embedded on a webpage? If yes, please share the URL so that we can further check. I checked your form and I can verify that it is working properly in Google Chrome and Mozilla Firefox.

It is possible that your users are using browser extensions or add-ons that are blocking the forms.

Do you know what browser are they using and what is the exact error message? If possible, please provide a screenshot so that can investigate further.

Also, do you know if they are accessing your forms in a university, office or at home?

Our forms are served across a protected, 256-bit Secure Sockets Layer (SSL) connection. We have an SSL certificate that uses SHA256 with RSA encryption for HTTPS. Also, our systems are regularly tested against external and internal threats.

For more information about our security, please check this page: https://www.jotform.com/security/.

Hope that helps. If you have any questions, let us know. Thank you for your understanding.