the way universal email works is to create the email message, hand it over to the SMTP server, from there, the SMTP server relays the message to the recipient.
The SMTP server will not make any sort of response back with the results, you would need to look into the SMTP servers error logs to see why it is not relaying the message. You would need to contact the host for this info.
It is possible that it is a problem with the from address. Some SMTP servers require the from address to be a valid email address on the smtp servers domain. If this is the cxase, you can set the from address to a hard coded value, then set the reply to address to use the form input.