e-newsletter error after already sending some emails.

I've installed the e-newsletter plugin, set up AWS SES and I was able to send a test and started my first email batch. When it reached 65 emails (my SES server is in production mode meaning i have 10K emails per day) i've been getting an error and can't finish the sending. The first error was

SMTP ERROR DATA NOT ACCEPTED. ERROR

Then after a few retries i got "error1" then it went back to the above error. I know for a fact that SMTP works. I know that the first 65 emails were received. I'm not sure what else to do to trouble shoot. Any help would be appreciated.