In our webiste, After user signup, we send an email with acitivation link to their email address. We are using PHP mail() to send a simple email. Until this point, we have checked with yahoomail, gmail, hotmail.. it works fine. But yesterday, we were checking with the microsoft outlook. No mail was sent, eventhough our user get confirmation stating that 'Activation link has been send to your email address.' Following is the excerpt of my code. I did some research on google. I could not find any definite answer. Any suggestions. Thank you.
$subject = 'Account Activation Code';
$message = '<html><body>';
$message .= '<table rules="all" background="http://www.example.com/webimage/emailbackground.jpg" width="633px" height="297px" cellpadding="10">';
$message .= "<tr><td height='52px' valign='bottom'><font color = '#fffc07' size = '4'><strong>Dear ".$firstname.' '.$lastname.','."</strong></font> </td></tr>";
$message .= "<tr><td height='160px' valign='top' > <font color = '#000000' size = '2'>
Thank you for signing up. Please use following link to activate your account.</font><br/><br/>";
$message .= "<strong>".$url."</strong> <br/><br/>";
$message .= "<font color = '#000000' size = '2'>Please do not reply to this message.</font> <br/><br/><br/></td></tr>";
$message .= "</table>";
$message .= "</body></html>";
$headers = "From:example<no-reply@example.com>\r\n";
$headers .= "MIME-Version: 1.0\r\n";
$headers .= "Content-Type: text/html; charset=ISO-8859-1\r\n";
if (mail($editedemail,$subject,$message,$headers)){
return TRUE; } else {return FALSE;}
