in message
sometimes i get a message of delivery notification delay - why?
The recipient's mail server is down or too busy to accept further
connections. You'll just have to wait. If the recipient's mail server
remain unresponsive for too long, like 10 or 24 hours (all depends on
what your sending mail server is configured for), then you'll get
another NDR (non-delivery report) e-mail saying your message could not
be delivered. You can't control the receiving mail server or the
network to reach it. Your sending mail server got your e-mail and
you'll have to wait to see if the receiving mail server ever accepts it.
