I am using first time mail function in php i get a code from online and it implemented to my program but its not working. Can any please help me to correct this ?
  <?php
     $to = "ganesh.sunraise@gmail.com";
     $subject = "This is subject";
     $message = "<b>This is HTML message.</b>";
     $message .= "<h1>This is headline.</h1>";
     $header = "From:lokesh.sunraise111@gmail.com ";
     $retval = mail ($to,$subject,$message,$header);
     if( $retval == true ) {
        echo "Message sent successfully...";
     }else {
        echo "Message could not be sent...";
     }
  ?>
 
     
     
    