Problems sending php email

Question

I am trying to send emails to specific lists registered in the database, with the php mail function but the email is not sent. What can be the mistake?

Below the script for sending emails:

if ($_SERVER["REQUEST_METHOD"] == "POST"){
    //realiza a conexão com o banco de dados
    require_once("includes/conexao.php");
    //monta o corpo da mensagem
    $corpo                  = file_get_contents("$_POST[mensagem]");
    //lista de e-mails que será enviada
    $lista                  = $_POST["lista"];
    //remetente (e-mail de quem envia)
    $remetente              = $_POST["remetente"];
    //pega o domínio do remetente
    $dominio                = substr(strrchr($remetente, "@"), 1);
    //assunto da mensagem
    $assunto                = $_POST["assunto"];

    //realiza o envio dos emails
    $sql                    = "SELECT DISTINCT email FROM dados WHERE lista = '".$lista."'";
    $query                  = mysqli_query($conexao, $sql);
    while($exibir           = mysqli_fetch_array($query)){
        //headers
        $destinatario       = $exibir["email"];
        $headers            = "MIME-Version:1.1"."\n";
        $headers           .= "Content-type: text/html; charset=utf-8"."\n";
        $headers           .= "To: <$destinatario>"."\n";
        $headers           .= "From: Teste de envio"."\n";
        $headers           .= "Reply-To: <no-reply@$dominio>"."\n";
        $headers           .= "Return-Path: <$remetente>"."\n";
        $envio              = mail($destinatario, $assunto, $corpo, $headers);
    }

Note: No error is returned.

Answer 1

First try to force the errors to show:

<?php

    ini_set('display_errors','On');
    error_reporting(E_ALL);

It may also be that the function mail(), is disabled in the kinghost, for several reasons, one of them is spam.

I advise to use Phpmailer, for sending via SMTP, it is safer and your email will not run the risk of falling into spam also.