First I would check in the Form Completion Events drop down to make sure you have an event there.
Some of the common mistakes I have seen made are below:
- Not selecting "Any Field Response" in the Dynamic Field question.
- Not clicking "Update Event". If you "Update Settings", it does not save the event.
- Not sure that it matters, but make sure you have a valid E-Mail address in the from.
Can you send E-Mail from other parts of your site? You can test this under Host Settings in the SMTP Server Settings.