Hello @StevenB617 ,   The issue likely stems from your contact's email program or network not immediately trusting the ccsend version of your From address that you're using.    Here are some general best practices for deliverability. Deliverability can have a lot of variables, from elements on our side, on your side, on the recipient's side, and in their email system company's side. Since the issue likely stems from using the ccsend rewrite for your from address for email authentication, I'd advise setting up self-authentication so you're sending using an address with your own, unique domain. With all the delivery gatekeeping and anti-spam/malware safeguards in place, it's become more and more necessary for businesses using an ESP to have this in place.   If you'd like to learn more about safelisting, and what it entails for your contact: Safelisting domains in a security system Safelisting email addresses in an email client or security system   If you're wanting more in-depth, specialized insight on your current deliverability, it'd be worth speaking with one of our Deliverability agents.   See also: Email Authentication FAQ ... View more