I have WordPress installed on IIS 7.0 on Windows Server 2008 R2. My email server (within the same LAN) is an Exchange 2010. I installed and activated the Configure SMTP plugin. I went to the setup page for the plugin and entered all the data regarding the mail server and then tried a test email. It failed with:
SMTP Error: Data not accepted.
SMTP server error: 5.7.1 Requested action not taken: message refused.
My Exchange server does not "relay" messages, so I thought that might be the problem. I therefore provided an SMTP username and password, checked the "Use SMTPAuth" box and tried the test again. The result was an error:
SMTP Error: Could not authenticate.
I know emails can be sent from web sites, as I have an ASP>Net site that uses code to send emails in a similar fashion.
I notice other posts similar to this here, all unresolved with answers. Would be nice to have some help. Thank you.