I have a IIS SMTP relay setup through my 2003 server. It was working up to 2 weeks ago, and no one has made any changes because I am the only one who has access to this server. I verified the credentials by logging into the office365 portal, verified that the port was open by connecting to smtp.office365.com on port 587 via telnet, and verified configuration based on the KB article "How to setup an SMTP relay on Office365 link. Also tried creating a ticket via the Office365 support site but cannot because the option on the site will not update when I click on technical support and the call tech support does not work either. When I do a telnet test, it keeps telling me that "client cannot authenticate".
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