Sory the english.
Just see the picture.
(http://img231.imageshack.us/img231/4011/petrolivbc8.jpg)
The Round Cube send the e-mails, but don't show the message "e-mail has be send Sucess"
Stay in one infity loop.
PS: Is the last version, i gess rc
Do you have any errors in your error log?
Same here (using english). The email is actually sent without problems, I "just" have to wait a while before I manually go back to the inbox (and it then appears if I go to the sent folder).
Nothing in the logs dir.
Another (related?) problem: new messages don't appear automatically in the inbox (the number of unread messages changes, but I have to go to another folder / come back to see them).