I've created another page in the root of the site named emailtest.php. It is a simple application of universal email and it doesn't send either.
Do you have access to the SMTP server logs? That might be able to shed light on the issue.
If you can set up a Universal Email page that works, then I can use that to debug and determine the difference, but it still appears to me that email isn't working in general from this site based on the two tests I've referenced.