Troubleshooting PHP Mail

That is quite a long story. A few bullet points (Assuming that mail() returns true and there are no errors in the error log) :

• Does the sender address ("From") belong to a domain on your server? If not, make it so.
• Is your server on a blacklist (e.g. check IP on spamhaus.org)? This is a remote possibility with shared hosting.
• Are mails filtered by a spam filter? Open an account with a freemailer that has a spam folder and find out. Also, try sending mail to an address without a spam filter.
• Do you possibly need the fifth parameter "-f" of mail() to add a sender address? (See mail() command in the PHP manual)
• If you have access to log files, check those, of course, as suggested above.
• Do you check the "from:" address for possible bounce mails ("Returned to sender")? You can also set up a separate "errors-to" address.

For german speakers, I have written a quite exhaustive "what to do" on this issue some time ago. See here.

I Finally got a laaaaarge smile on my face. Working together with @DaveRandom, He helped me come up with these codes:

NOTE: The code bellow uses PHPMailer

    <?php

            $senderName = 'Erick Best'; //Enter the sender name
            $username = 'erickbestism@yahoo.com'; //Enter your Email
            $password = 'passwordHere';// Enter the Password


            $recipients = array(
                'erickbestism@gmail.com' => 'Erick Best',
                'erickbestism@yahoo.com' => 'Yahoo User',
            );
          ///That's all you need to do

//No need to edit bellow    
            require '../PHPMailerAutoload.php';

            //Create a new PHPMailer instance
            $mail = new PHPMailer();

            // Set up SMTP
            $mail->IsSMTP();
            $mail->SMTPAuth   = true;
            $mail->SMTPSecure = "tls";
            $mail->Host       = "smtp.mail.yahoo.com";
            $mail->Port       = 587; // we changed this from 486
            $mail->Username   = $username;
            $mail->Password   = $password;

            // Build the message
            $mail->Subject = 'PHPMailer mail() test';
            $mail->msgHTML(file_get_contents('contents.html'), dirname(__FILE__));
            $mail->AltBody = 'This is a plain-text message body';
            $mail->addAttachment('images/phpmailer_mini.gif');

            // Set the from/to
            $mail->setFrom($username, $senderName);
            foreach ($recipients as $address => $name) {
                $mail->addAddress($address, $name);
            }

            //send the message, check for errors
            if (!$mail->send()) {
                echo "Mailer Error: " . $mail->ErrorInfo;
            } else {
                echo "Message sent!";
            }

        ?>

And this WORKED like VOODOO!... It sent mails to any provider. Including **YAHOO**

Hope it helps someone!

You can get around the MX lookup by adding a short entry into your sendmail /etc/mail/mailertable file.

The contents of the file should probably have a single line like:

bresnan.net       esmtp:[69.145.248.18]

Save the file and restart sendmail (or rebuild your sendmail.cf if it must be done manually).