Dequeue messages failed whith invalid domain name

[Oktopuce]

If the messenger queue contains an email address with an invalid domain name, this blocks the sending of all other emails until you manually delete the email address in error in the queue.

The scheduler task "Dequeue (messenger)" always failed with this use case with the message:

Execution of task "Dequeue (messenger)" failed with the following message: Expected response code "250/251/252" but got code "450", with message "450 4.1.2 [<name.firstname@invalid-domain.com>](mailto:name.firstname@invalid-domain.com) [<name.firstname@invalid-domain.com>](mailto:name.firstname@invalid-domain.com): Recipient address rejected: Domain not found".

Because error code 450 is a temporary error code, in order to correct this error, may be you can check the DNS with code like this:

$domain = substr(strrchr($email, "@"), 1);

if (!checkdnsrr($domain, 'MX')) {
    // Invalid domain → remove address  from queue
}