Can anyone explain how to correct this error? I receive this when running the mail flow troubleshooter. Error submitting mail Mail submission failed: Error message: The SMTP server requires a secure authentication or the client was not authenticated. The server response was: 5.7.1 Client was not authenticated.

Hi,Is there any error about the mail flow? From internet to internal, from internal to internal , client to server,or any other?Does this post help?http://social.technet.microsoft.com/Forums/en/exchangesvrtransport/thread/3e5c998a-273e-4145-9930-9620d3fb9d77If not, please provide more information about your organization environment. Frank Wang

Hi,That link worked like a charm. My anoymous users box was not checked in either the Client or Default receive connector. When I checked the box for both, the mail acceptance test passed.I'm now wondering if maybe that was causing the delay in receiving our emails.

No, it won't.By default, your exchange server need to accept the anoymous connection from the outside SMTP server, becase the SMTP server open an anoymous link to another SMTP server by default.Sorry, but you care of causing the delay or relay?If it is relay, you can find more information in Technet article:How to Allow Anonymous Relay on a Receive Connectorhttp://technet.microsoft.com/en-us/library/bb232021(EXCHG.80).aspx<!---->Frank Wang