Update 08/09/15 @ 09:10: This issue was monitored until the close of business on 07/09/15 and having identified no further problems, the issue was confirmed as resolved.
04/09/10: We are currently experiencing a problem with AuthSMTP authentication resulting in users being unable to send emails using the AuthSMTP.datanet.co.uk outgoing mail server.
We are working on the issue and apologise for the inconvenience.