I’ve set the backup module to send a mail only in case of error.
But i’ve discovered that mail address on aruba mail, on joomlahost, or libero don’t accept mail from a unqualified mail server (no public domain, no spf, no dkim) . So, on that mail address we never receive the alert on error. The mail are simply rejected by aruba (or other) mail server. Not even marked as spam in the mailbox, are simply completely rejected and never notified in any way.
To mail address on gmail works all fine. First time you will receive the alert mail marked as spam in the spam box, but if you mark it as not spam, after all works fine.
There is a way to send the alert mail through an external smtp server as many commercial nas ? It will be wonderful !