发出执行CRON Job的问题

I have set up a cron job to do email out meeting reminders for my customers, but it doesn't appear to be working. Yet, when I load the page manually, it works and echo's just fine. Can someone help?

My script that I'm trying to run is as shown below.

require('../../dbconfig.php');
$sql    = " SELECT email, name, webinar_date FROM webinar_list";
$query  = mysqli_query($conn, $sql);
while ($row=mysqli_fetch_assoc($query))
{

    $email = $row['email'];
    $name = $row['name'];
    $webinarTime=$row['webinar_date'];
    echo "current time = ".$currentTime=time(); echo "<br>";
    echo "registered time = ".$registeredTime=strtotime($row['webinar_date']); echo "<br>";
    echo "Difference = ".$timeDiff=$currentTime - $registeredTime;

    //IF TIME DIFFERENCE IS <60 MIN BUT LESS THAN 55MIN
    if(($timeDiff<=3600)&&($timeDiff>=3300))
    {
         $message = oneHour($name); 
         echo $message;
         $from    = "reminder@theleagueoffreedom.com";
         $to      = $email;
         $subject = 'Just A Friendly Reminder...';
         $headers = "From:  Anthony Moto 
";
         $headers .= "MIME-Version: 1.0
";
         $headers .= "Content-Type: text/html; charset=UTF-8
";
         mail($to,$subject,$message, $headers);
    }
    //IF TIME DIFFERENCE IS <10 MIN BUT GREATER THAN 5MIN
    elseif(($timeDiff<=600)&&($timeDiff>=300))
    {   
         $message = tenMinutes($name); 
         echo $message;
         $from    = "reminder@EXAMPLE.com";
         $to      = $email;
         $subject = 'RE:10 Minutes...';
         $headers = "From:  Anthony Moto 
";
         $headers .= "MIME-Version: 1.0
";
         $headers .= "Content-Type: text/html; charset=UTF-8
";
         mail($to,$subject,$message, $headers);
    }
    //IF TIME DIFFERENCE IS <5 MIN BUT LESS THAN -5MIN
    elseif(($timeDiff<=300)&&($timeDiff>=-300))
    {
         $message = liveTraining($name);
         echo $message;
         $from    = "reminder@EXAMPLE.com";
         $to      = $email;
         $subject = 'We Are Starting NOW!';
         $headers = "From:  Anthony Moto 
";
         $headers .= "MIME-Version: 1.0
";
         $headers .= "Content-Type: text/html; charset=UTF-8
";
         mail($to,$subject,$message, $headers);
    }
}

I return $message variable in the functions I call which is a string of letters. My cron job looks like this.

*/10    *   *   *   *   /usr/local/bin/php -q /home/username/public_html/example.com/webinar_emails/p0/webinar_reminder.php

If it helps, the currentTime is taken from SQL and it is in this format:

2016-11-27 11:00:00

The issue that I'm having is that I don't get any emails at all. I've checked my spam folder as well. I don't even get a "blank" email. And like I said, the code echo's out the current time and time difference just fine. But the Cron doesn't appear to be running the script.

Any help would be appreciated and I will be forever grateful!

Thanks