Confirmation emails do not arrive in Comcast.net email boxes

I have an autoresponder email on my 9 forms that automatically respond to the email address input. Comcast.net email service does not seem to accept these emails. You can't even find them in the spam folder. They don't arrive at all. Is there anything you can do.

I have checked your email history and noticed that all the emails have been sent successfully, you could also check your email history by following this guide: How-to-View-All-Your-Form-Email-History

May be that somehow email from JotForm are being blocked, I would suggest you to set up an SMTP sender instead, this guide will help you doing so: How-to-Setup-SMTP-for-a-Form

If you are also using a Comcast email address then this guide will help you getting your SMTP details: http://www.serversmtp.com/en/smtp-comcast 

Hope this helps.