PHP mail() inside a foreach loop

Question

I got a cronjob that executes a PHP script every 5 minutes in order to send a welcome letter to new members.
My goal is to fetch the data from MySQL, pull it into an array, loop through the results and mail each result to a recipient using PHPs mail() function.
The mail() part is not working for some reason and I am 100% sure that mail()is configured and working because I can use mail() outside the foreach loop.

Example code below:

Fetch data from MySQL and store it in an array:

while ($row = $result->fetch_assoc()) {
  $tickets[] = array($row['id'], $row['namn'], $row['epost'], 
  $row['meddelande'], $row['datum']);
}

$tickets is an array.

Loop through the results and mail it:

foreach ($tickets as $ticket) {
    if (mail("mymail@example.org", "Msg from $ticket[1]", "$ticket[3]", "From: $ticket[2]")) { // Always called, but doesn't send the mail
        $query = 'UPDATE ticket SET skickat = 1 WHERE id = ?';
        if ($stmt = $db->prepare($query)) {
            $stmt->bind_param('s',$ticket[0]);
            $stmt->execute();
        } else {
            sleep(5);
            $query = 'UPDATE ticket SET skickat = 1 WHERE id = ?';
            $stmt = $db->prepare($query);
            $stmt->bind_param('s',$ticket[0]);
            $stmt->execute();
        }
    } else {
        die('The email could not be sent');
    }
}

The code works, and it updates the MySQL record to skickat = 1 so I know that the code got executed how ever, it doesn't send the mail.
I don't have access to the error.log that Apache creates and I get no errors with PHP errors turned on.

What am I missing?
I'm using Apache 2 with PHP 7

Answer 1

The problem you're encountering likely has to do with your hosting setup. To prevent spam, many hosting providers do not allow many emails to be sent quickly. You can likely resolve this by adding:

sleep( 5 ); // causes the script to wait for 5 seconds

after your if statement.