I was setting up an autoresponder in chronoforms and was getting the following error.
chronoforms_5_autoresponder

The first email to the site owner went and “your message was sent” displayed, but the autoresponder email element was causing the “Mailer Error”.

I had “email” in the Dynamic to field; however, the I got this error.

How I fixed it was by using a legitimate email address in the “from email” field in the first part of the email element in the setup tab of chronoforms.

I hope this helps someone else out there…