Hello, I'm attempting to send an email to a customer support staff member. We've already had quite a bit of correspondence from these same accounts, not sure why this error would come up? Do I now need to whitelist this email address (and how do I do that)? I am emailing from the same location I always have.

Only other reason I can think of is inside the text body I included a personal gmail address. Test emailed that address and it delivered no problem, so spam alert is unlikely that. Ticket below: