When a email cannot be sent (bad address email for example) it remain in BDD

So, at each new call to email_send_all when a bug is updated for example, mantis try to sent again the mail with invalid address... so the update of bugs is very slow because of timeout of this invalid email

A solution is to change the default value of the arg delete on failure in the email_send_all function from false to true... and truncate the table of emails in mantis tu delete old email which haven't be sent...

But it's very inconvenient, sending email is (without errors) very slow, but if invalid email will be sent and sent at each new update, first that doesn't make sense, and two, that's slowing mantis...