what is a "Bounce List" email

Email bouncing means that the email wasn't delivered to the email recipient for some reason (reasons can vary). 

There are several reasons why an email address may have been added to the bounce list. It could be due to a non-existent/inactive email address, your mail server being unavailable, your email server has rejected the emails due to suspected spam, your mailbox is full or JotForm is on your blacklist. JotForm will stop sending emails when your email address is on the bounce list.

I checked your account and the account email address is not on the bounce list. Please let us know if you are facing any email bounce issues.

Here's a related guide: https://www.jotform.com/help/208-How-to-Prevent-Email-Bouncing-Related-Issues 

Let us know if you have any further queries.