Mail error message

[Tezread]

Im getting an error message as follows:

Warning: mail(): SMTP server response: 550 5.7.1 Unable to relay for [e-mail] in C:\Program Files\Apache Group\Apache2\htdocs\titlehelp.php on line 16

Something went wrong try again or contact the system administrator.

I was wondering how to resolve this. Here is my code for info:

<?php
// If you wished, you could also save this information to a database
$FirstName = $_POST['LastName'];
$LastName = $_POST['FirstName'];

$Email = $_POST['Email'];
$Enquiry = $_POST['Enquiry'];

$formsent = mail('[e-mail]', 'An Enquiry from Minds Eye website', "Enquiry from: $LastName $FirstName\r\nYear: $Email\r\nThe enquiry is: $Enquiry", "From: $Email\r\nBounce-to: [e-mail]");
if ($formsent) {
echo "<P>The enquiry you made has been sent to Minds Eye.</P>";
}
else {echo "<P>Something went wrong try again or contact the system administrator.</P>";
} 

?>
</body>
</html>

[execute]

check whether the email was received just incase.
use @ in front of mail to surpress warnings..
Or just remove the variable in front of mail and also try not to use single quotes.

But it should work, maybe something wrong with your SMTP server

[Tezread]

I have changed my php.ini settings to sendmail_from smtp.entadsl.com and changed mail to pop.entadsl.com. I get no error messages but im not sure if im sending mail to the right address. I want it to go to [e-mail].

Any pointers? thanks in advance

[Tezread]

I tried out your suggestions and still not having any joy. Has this happened to anyone else and if so what did you do?