Strange Email Error - Won't send form Automation, but sends from Script Sandbox

I have hit a very strange error when developing an automation. Emails were not going out, so i did all sorts of troubleshooting until I ended up with an automation that JUST sends an email with text, no variables, for subject, body, and toemail. This email sends fine in the script sandbox but throws the following error when triggered via Automation. What am I doing wrong, is this a bug?

UnknownException: Sending email reported failure. (An unexpected error prevented your requested action from completing. The error has been logged for the administrator to review.) ---> System.Exception: Sending email reported failure.