if (isset ($name)) {
    $name = substr($name,0,20);
    if (empty($name)){
        echo "<center><b>error<p>";
        exit;
    }
} else {$name = "error";}

if (isset ($email)) {
    $email = substr($email,0,20);
    if (empty($email)) {
        echo "<center><b>error<p>";
        exit;
    }
} else {$email = "error";}

if (isset ($mess)) {
    $mess = substr($mess,0,1000);
    if (empty($mess))
    {
        echo "<center><b>error<p>";
        exit;
    }
} else {$mess = "error";}

$i = "error";

if ($email == $i AND $mess == $i) {
    echo "error";
    exit;
}

$to = "my email";
$subject = "Letter from mywebsite";
$message = "$name;$email;$mess;$REMOTE_ADDR";
mail ($to,$subject,$message) or print "error";
exit;
?>

SMTP -> get_lines(): $data was ""SMTP -> get_lines(): $str is "220 TAG.Hosting mail service. "SMTP -> get_lines(): $data is "220 TAG.Hosting mail service. "SMTP -> FROM SERVER:220 TAG.Hosting mail service. CLIENT -> SMTP: EHLO www.mlmtechnology.ru SMTP -> get_lines(): $data was ""SMTP -> get_lines(): $str is "250-gamma.tagtech.ru Hello www.mlmtechnology.ru [83.166.99.194] "SMTP -> get_lines(): $data is "250-gamma.tagtech.ru Hello www.mlmtechnology.ru [83.166.99.194] "SMTP -> get_lines(): $data was "250-gamma.tagtech.ru Hello www.mlmtechnology.ru [83.166.99.194] "SMTP -> get_lines(): $str is "250-SIZE 104857600 "SMTP -> get_lines(): $data is "250-gamma.tagtech.ru Hello www.mlmtechnology.ru [83.166.99.194] 250-SIZE 104857600 "SMTP -> get_lines(): $data was "250-gamma.tagtech.ru Hello www.mlmtechnology.ru [83.166.99.194] 250-SIZE 104857600 "SMTP -> get_lines(): $str is "250-PIPELINING "SMTP -> get_lines(): $data is "250-gamma.tagtech.ru Hello www.mlmtechnology.ru [83.166.99.194] 250-SIZE 104857600 250-PIPELINING "SMTP -> get_lines(): $data was "250-gamma.tagtech.ru Hello www.mlmtechnology.ru [83.166.99.194] 250-SIZE 104857600 250-PIPELINING "SMTP -> get_lines(): $str is "250-AUTH PLAIN LOGIN "SMTP -> get_lines(): $data is "250-gamma.tagtech.ru Hello www.mlmtechnology.ru [83.166.99.194] 250-SIZE 104857600 250-PIPELINING 250-AUTH PLAIN LOGIN "SMTP -> get_lines(): $data was "250-gamma.tagtech.ru Hello www.mlmtechnology.ru [83.166.99.194] 250-SIZE 104857600 250-PIPELINING 250-AUTH PLAIN LOGIN "SMTP -> get_lines(): $str is "250 HELP "SMTP -> get_lines(): $data is "250-gamma.tagtech.ru Hello www.mlmtechnology.ru [83.166.99.194] 250-SIZE 104857600 250-PIPELINING 250-AUTH PLAIN LOGIN 250 HELP "SMTP -> FROM SERVER:250-gamma.tagtech.ru Hello www.mlmtechnology.ru [83.166.99.194] 250-SIZE 104857600 250-PIPELINING 250-AUTH PLAIN LOGIN 250 HELP CLIENT -> SMTP: MAIL FROM: SMTP -> get_lines(): $data was ""SMTP -> get_lines(): $str is "250 OK "SMTP -> get_lines(): $data is "250 OK "SMTP -> FROM SERVER:250 OK CLIENT -> SMTP: RCPT TO: SMTP -> get_lines(): $data was ""SMTP -> get_lines(): $str is "550-Verification failed for "SMTP -> get_lines(): $data is "550-Verification failed for "SMTP -> get_lines(): $data was "550-Verification failed for "SMTP -> get_lines(): $str is "550-Unknown user "SMTP -> get_lines(): $data is "550-Verification failed for 550-Unknown user "SMTP -> get_lines(): $data was "550-Verification failed for 550-Unknown user "SMTP -> get_lines(): $str is "550 Sender verify failed "SMTP -> get_lines(): $data is "550-Verification failed for 550-Unknown user 550 Sender verify failed "SMTP -> FROM SERVER:550-Verification failed for 550-Unknown user 550 Sender verify failed SMTP -> ERROR: RCPT TO command failed: 550-Verification failed for 550-Unknown user 550 Sender verify failed