Remote users unable to send using Exchange 2010 OWA

emailexchange-2010outlook-web-appsmtp

I am unable to send emails (email is send but never delivered) using OWA, from different remote locations using different ISPs. When I send emails from these remote locations relaying over available ISP, emails are being sent just fine.

Where should I look for problems in Exchange settings

  • accepted domains
  • send connectors
  • receive connectors.

Checking the message queue I have found the following error message

The message has been queued on server 'server.domain.local' since
2/26/2012 11:57:47 AM. The last attempt to send the message was at
2/26/2012 12:05:29 PM and generated the error '451 4.4.0 Primary
target IP address responded with: "451 5.7.3 Require basic
authentication." Attempted failover to alternate host, but that did
not succeed. Either there are no alternate hosts, or delivery failed
to all alternate hosts.'.

What could cause this problem?

Thanks

Best Answer

The first question is where does the failure appear? Inside the exchange organisation or in emails sent outside the organisation? So the first question is does the error appear for internal emails, external emails, or both? OWA is obviously an exchange component in its own right, and so the emails are accepted by the exchange system the moment you click send, so we can assume that you've got a basic working system of some kind set up.

For external emails, as you say this is where the problem lies, I'd be looking at the SMTP send connector(s) for the organisation. You've got a box installed with the exchange hub transport role, and you might have another box configured as an edge transport server.

So the question is do you have an edge server? And what queues are showing issues? Are you using the default address space scope/ email routing? Are you using a smarthost? Is there a firewall between any of these servers? This is where I would start digging for the problem.

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