Why am I no longer receiving email alerts for new form submissions?

I no longer receive email notifications when someone submits a form. My email provider is Comcast. 

Your email address is not listed in our bounce list, the messages are marked as successfully sent according to your account email history.

You may try whitelisting emails coming from noreply@jotform.com. Please also check a Spam/Junk folder and mark the messages as not spam (if any).