Site URLs:  https://wickslake.com/contact/ and  https://wickslake.com/rentals/

The Gravity Forms on each of the above pages are created to send Notifications to Zoho accounts based on role, for example, president@wickslake.com, secretary@wickslake.com, rentals@wickslake.com. 

We are using SendGrid for SMTP. Our troubleshooting indicates the following error.

554 5.2.3 MailPolicy violation Error delivering to mailboxes

The emails do not exceed 25MB and consist of general information as shown on the page URLs.