having the same problem too. I send douzens of emails, but i can't really know IF THEY WERE SENT OR NOT, cause they always remain in Draft box. Quite frustrating (and dangerous)...
(And sometimes mails were sent void/empty) The problem first happened sometimes, but since few days it happens regularly!
I am choosing not to use any more this extension, but classic not tracked email sending.
Please fix it as soon as possible! Thx