I am re-opening this since it seems to be the same issue I am having. I just got approved for SES production use.
When I add my API keys which I know are correct I get an error 512 when trying to send a message. I did verify the email address and domain via SES. See link below, these are the two messages i keep getting.
https://goo.gl/D20xL5
Additionally it says test has been sent but I never actually see the email. Thoughts?