"Incomplete Headers" with PHP's mail() function

Question

[Sat Apr 25 04:18:46.660552 2015] [fastcgi:error] [pid 11271:tid 140464355243776] [client 95.87.236.146:63037] FastCGI: comm with server "/usr/lib/cgi-bin/php5-fcgi-domain.cc" aborted: idle timeout (30 sec), referer: http://domain.cc/login/restore_session.php?redirect=yes
[Sat Apr 25 04:18:46.660673 2015] [fastcgi:error] [pid 11271:tid 140464355243776] [client 95.87.236.146:63037] FastCGI: incomplete headers (0 bytes) received from server "/usr/lib/cgi-bin/php5-fcgi-domain.cc", referer: http://domain.cc/login/restore_session.php?redirect=yes

I am getting these errors in my error.log file. This happens when I try to send an email with the mail() function:

$to = $ticket->email;
$subject = "X Support";
$message = "We have just answered your support ticket! Here is our message: \n\n-------------\n\n" . $text . "\n\n-------------\n\nIf you wish to reply, please visit http://domain.cc/support.php";
$headers = "From: [email protected]\r\n" .
"Reply-To: [email protected]\r\n" .
"X-Mailer: PHP/" . phpversion() . "\r\n";
$headers .= "CC: [email protected]\r\n";
$headers .= "MIME-Version: 1.0\r\n";
$headers .= "Content-Type: text/html; charset=ISO-8859-1\r\n";
$result = mail($to, $subject, $message, $headers);

I'm calling this code with AJAX and as a result when I click "Send Reply", the page just hangs and I get 500 error as a response after 30 seconds. The weird thing is that this code used to work fine for a few months.

EDIT: I forgot to mention - the emails get delivered anyway.

Answer 1

In your setting, the connection between Apache and PHP is done with a variant of CGI, fastcgi. That's why you're seeing fastcgi:error in your logs. When Apache receives a request for an URL that's a PHP file, say "my-site.tld/index.php", it passes the request along to PHP. Then PHP "does it's thing" and sends back its output. That PHP output then gets send out by Apache to the client who did the request.

But Apache doesn't wait forever for PHP to answer. There's an "idle timeout" of 30 seconds. After that's gone by, Apache assumes that PHP won't be sending an answer anymore. That's what's happening in your case, as you can see in comm with server "/usr/lib/cgi-bin/php5-fcgi-domain.cc" aborted: idle timeout (30 sec). So Apache doesn't have anything to send back to the client who did the request, not even (complete) headers, because it received only 0 bytes from PHP: incomplete headers (0 bytes) received from server "/usr/lib/cgi-bin/php5-fcgi-domain.cc"

The conclusion is: For some reason, the execution of your code takes PHP longer than the timeout of 30 seconds. That triggers Apache to think "I've waited long enough, there won't be an answer". The next question you should look into IMHO, what makes your PHP code take so long.

One possible approach would be to remove/comment out parts of the code and see if the rest gets executed within the 30 seconds limit. Does it still break the timeout limit when you only do $to = $ticket->email;? Next step, does it still break the limit when you only do the first two lines and so forth. If that's the most feasable approach depends on the details of your setting and work environment.

Answer 2

    $headers  = 'MIME-Version: 1.0' . "\r\n";
    $headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
    $headers .= 'To: Segreteria <[email protected]>' . "\r\n";
    $headers .= 'From: Gestore corrispondenza ZENITH <[email protected]>' . "\r\n";

These are my headers for the mail function and they are working well with different smarthosts. Can you try with these and see if you get any further error?