PHP

wordpress Warning: Cannot modify header information - headers already sent by

<?php
add_action('template_redirect', function () {
    ob_start();
});

Cannot modify header information - headers already sent by

Solution:

$msg_email = 'Email enviado com sucesso!';
header('Location: ../login.php?msg_email=' . $msg_email);
$mail->send();

Error - Cannot modify header information - headers already sent by ... :
$mail->send();
$msg_email = 'Email enviado com sucesso!';
header('Location: ../login.php?msg_email=' . $msg_email);

Warning: Cannot modify header information - headers already sent by - setcookie

output_buffering = On

Warning: Cannot modify header information - headers already sent by

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