When there is a problem with one of the mailboxes, just skip it

What did you do?
When I set up multiple mailboxes, if there is a problem with one of the mailboxes, the logic here will reject the sending of notifications from all other normal mailboxes. Is this reasonable? Is it possible to skip the mailbox in question?

// notify/email/email.go
// Notify implements the Notifier interface.
func (n *Email) Notify(ctx context.Context, as ...*types.Alert) (bool, error) {
... ...
	for _, addr := range addrs {
		if err = c.Rcpt(addr.Address); err != nil {
			return true, errors.Wrapf(err, "send RCPT command")
		}
	}
... ...

What did you expect to see?
skip the email which has problem, and send messages to other normal emails

What did you see instead? Under which circumstances?
it will skip all emails.

Start in notify/email/email.go at Email.Notify, especially the loop calling c.Rcpt for each address. Confirm how a failed mailbox currently stops notification delivery; done means the problematic mailbox is skipped while messages still reach the other valid addresses.