Why does a form recipient email get added to the bounce list?

We have a form that's been in use for over 3 years, sending to the same email. Why does an email suddenly get added to the bounce list?

Thanks,
Karen

I see that on a 'LAR Supply and Drug Request Form' the Autoresponder recipient email is configured improperly. You may need to change it to the 'Requestor E-mail' field.

If you are referring to something else, please provide us with the affected email address so we will be able to take a look.

The form in question is this one: https://form.jotform.com/43494712602958
And it’s the Notification 1 email, set to email TLT-media@kumc.
As mentioned, it’s been sending email just fine, up until today, when the email was on the bounce list. What prompts an email to get moved to the bounce list?
...

Are you getting a message about the bounce list somewhere? The email address in question is not listed in our bounce list, and emails logs look good.

If some email messages are not being delivered, please check a Spam/Junk folder. We can also suggest whitelisting the noreply@jotform.com email sender and adding it to the contact list if possible.

Right. After the recipient was notified by two individuals who submitted the form, but were not contacted regarding their request, and were able to provide proof of their submission.
Therefore, I checked the bounce list…the email was on the bounce list, so I removed it to take care of the customer’s needs.
I still want to know HOW THE EMAIL ENDED UP ON THE BOUNCE LIST when it’s been in use as the form’s recipient for over 3 years.
...

There are several reasons why an email address is added in the bounce list.

You may check this guide for more information.

Guide:How-to-Remove-Your-Email-Address-from-Bounce-List

You can also whitelist our default email list.

Guide:https://www.jotform.com/help/145-Whitelisting-JotForm-IP-Addresses-and-Domains

Hope this information helps.

If you need further assistance, let us know.