Mailqueue status messages

If DEFENDO's mail server fails to deliver an email you can find further information in "Monitoring -> Mail server". The following list explains the most common messages:

host map: lookup (DOMAIN): deferred

Name resolution of the target domain failed. This can be caused by problems with DEFENDO's or an upstream DNS. There could also be a problem with the recipients domain itself.

IO error

An in transit error occured. Maybe the dial-up connection hung up while delivering the mail or the recipient mail server terminated the connection (e.g. because the delivery of a very large mail took too long).

Connection refused

The recipient mail server is down. If outbound mail is forwarded to the relay of your provider you should check the configuration or contact the provider.