I am getting "systemEmailId is not a valid Id" with valid emails - any advice?

I am getting “systemEmailId is not a valid Id” with valid emails - any advice?. I have tried a few other email addresses and it’s not working.

found a solution? I got this today, too

I just got this issue as well.

This has happened to us at least twice in the last few days.

The email address was valid — in both cases, the same automation sequence, which sends two emails, sent the second email successfully.

Since no one else had posted their resolution yet, here is what Keap told me today that worked for this error message:

They had me resave that specific email inside the automation it was located in, as if I made a change to it, and then republished the campaign. This error message can happen if someone has opened the email to look at it within the automation, even if no changes were made. So anytime this error happens, that action should resolve it. In this case, this solution worked for us.