Cannot send multiple email Yii2 - php

Question

I working with framework Yii2 and I want send mail with Mailing. 1 email address sent successfully but array email address sent fail and Show error message:
Exception 'Swift_RfcComplianceException' with message 'Address in mailbox given [xxx#gmail.com,xxx#gmail.com] does not comply with RFC 2822, 3.6.2.'
My code send mail:
Yii::$app->mailer->setTransport([
'class' => 'Swift_SmtpTransport',
'host' => 'smtp.gmail.com',
'username' => $valueEmailSystem->username_mail,
'password' => $valueEmailSystem->password_mail,
'port' => $valueEmailSystem->port,
'encryption' => 'tls',
]);
$message = Yii::$app->mailer->compose();
$message->setFrom([$valueEmailSystem->username_mail => 'TEST']);
$str = implode(',', (array)$modelUser);
$message->setBcc($str);
$message->setSubject('Xác nhận yêu cầu');
$strUserName = implode(',', (array)User::getNameById($pk));
foreach ($valueContent as $key => $item) {
$reValue = str_replace("[hoten]",$strUserName,$item->value);
$message->setHtmlBody($reValue);
}
$message->send();
Help me! Thank all.

Answer 1

The problem is that you are imploding the addresses into one string. The setBcc() method accepts one address as string or multiple addresses as array, for example like that:
$message->setBcc(['first#example.com', 'second#example.com']);
Or if you want to specify names
$message->setBcc([
'first#example.com' => 'First Person',
'second#example.com' => 'Second Person',
]);
Documentation of method.