Multiple php email issue - php

Question

For my project I had to create a function that sends two email. One to the customer and the other to the a seller. Both emails will have different contents.
I wrote the two function using the standard PHP mail function as below.
$to = "xxxx#xxxx.com";
$subject = 'xxxx';
$message = "hello"
$headers .= 'MIME-Version: 1.0' . "\r\n";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
mail($to, $subject, $message, $headers);
Now, While testing the system on my own company's web server both emails seems to be sent and received. However, when I migrated the same system into an external server. only one email gets sent. primarily, the first email in the stack.
While I suspect the issue has something to do with the later server configuration, I am wondering where should I go next to debug this issue.

Answer 1

There were a few things in your "posted" code that were missing.
A missing semi-colon at the end of $message = "hello" (unless that was a typo/paste error?) and a dot in the first $headers
Also, not having a From: header attribute will surely result having the Email sent to and regarded as SPAM.
Having fixed those issues and added extra header information, the following code worked and did not end up in my SPAM, but the INBOX successfully.
<?php
$to = "xxxx#xxxx.com";
$email = "email#example.com";
$subject = 'xxxx';
$message = "hello";
$headers = 'MIME-Version: 1.0' . "\r\n";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
$headers .= "From: $email" . "\r\n" .
"Reply-To: $email" . "\r\n" .
"X-Mailer: PHP/" . phpversion();
mail($to, $subject, $message, $headers);
?>
Or with a success echo'ed message:
<?php
$to = "xxxx#xxxx.com";
$email = "email#example.com";
$subject = 'xxxx';
$message = "hello";
$headers = 'MIME-Version: 1.0' . "\r\n";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
$headers .= "From: $email" . "\r\n" .
"Reply-To: $email" . "\r\n" .
"X-Mailer: PHP/" . phpversion();
if(mail($to, $subject, $message, $headers))
{
echo "Message sent.";
}
else{
echo "Something went wrong.";
}
?>
Visit the PHP.net website for more information on the mail() and header() functions.
http://php.net/manual/en/function.mail.php