smtp error in php code

Question

I have the following problem,

here is the configuration file:

define('MAIL_HOST','xxxxx');         
define('MAIL_USER','xxxxx');                
define('MAIL_PASS','xxxxx');            
define('MAIL_FROM','xxxxx');    
define('MAIL_NAME','xxxxx'); 

here is the file that makes the e-mail call:

$mail = new PHPMailer();
$mail->SetLanguage("br", "smtp/"); //Idioma
$mail->IsSMTP();
$mail->SMTPDebug = 2;
$mail->SMTPAuth = true;
$mail->Host     =   MAIL_HOST;          
$mail->Username =   MAIL_USER;          
$mail->Password =   MAIL_PASS;          
$mail->From     =   MAIL_FROM;          
$mail->FromName =   MAIL_NAME; 

and here’s the mistake that happens when I tell you to proceed:

SMTP -> FROM SERVER:220-servidor.universeservidor.com.br ESMTP Exim 4.91 
          #1 Sat, 02 Mar 2019 21:14:43-0300 220-We do not 
              authorize the use of this system to transport unsolicited, 
              220 and/or bulk e-mail.
SMTP -> FROM SERVER: 250-servidor.universeservidor.com.br Hello localhost[177.12.86.71] 
          250-SIZE 52428800 250-8BITMIME 250-PIPELINING 250-STARTTLS 250 HELP
SMTP -> ERROR: AUTH not accepted from server: 503 AUTH command used when not advertised
SMTP -> FROM SERVER:250 Reset OK
SMTP Error: Could not authenticate. A mensagem nao pode ser enviada.

Erro do envio: SMTP Error: Could not authenticate.

_{Error image}