Who is your hosting company?
What have you entered for the From Address in the Universal Email settings? For many hosts this must be a valid email address for your domain.
make sure you are not using the same address for both the To address and the From address. many SMTP servers will not relay the email if you use the same address for both.
some SMTP Servers will require that you provide the From address as a an extra parameter, there is an option for the on the SMTP servers tab.
In Universa lEmail, did you set a go to page? If so, when you submit the form does it redirect properly?
on the go to page, try adding the following code:
<?php @session_start(); var_dump($_SESSION); ?>
this will write the session contents to the page including the status of sending the email to the SMTP Server, it will return success or failure. if it returns success, there is either an issue on the smtp server end, or the settings for sending the email are not correct.
if you need further help,, include a link to your contact form and a copy of the page and the webassist/email folder in a zip file.