I was minding my own business on my computer today when I noticed two emails in my Outlook 2007 outbox, seemingly stuck and going nowhere. I checked to see what the problem was and got this error: “None of the Authentication Methods Supported By This Client Are Supported By Your Server”. Thanks Microsoft, very informative. What the hell does that even mean and why is it happening all of a sudden?

I was thinking about what had changed recently and then I remember earlier today I had installed the latest batch of Windows Updates. Went through the list and sure enough, an update for Outlook 2007 had been installed (KB2412171). Now to the task of finding out what that update had changed and revert it or if I couldn’t revert the change, uninstalling the update. As it turns out, there was one setting that the update apparently changed. For many email accounts one is supposed to check the “My outgoing mail server requires authentication” meaning Outlook must provide username and password for the mail server to accept and relay outgoing emails. I knew the error was in the general area of authentication so I unchecked that option and the emails left, no problem.

Good, I thought, problem solved… only to receive two emails shortly after, where I was informed that my ongoing emails had been rejected at the recipients’ servers because they were not authenticated (a security measure to avoid somebody from just spoofing the sender’s email address and be able to send emails in your name without having to provide a password). OK so that brings me back to square one. What else could have changed? Turns out there is a setting in Outlook that uses a certain protocol when providing credentials to the web mail server to be allowed to send emails, called Secure Password Authentication (SPA). That was checked, but I could have sworn I didn’t set it that way. So I unchecked it, while leaving checked the earlier setting (“My outgoing mail server requires authentication”) and that did it.

Thought I pass it on to you in case the same happens to your computer.

Also, many Outlook  users have reported problems after installing this update, namely loosing the ability to archive old emails, and an extreme slowness when switching between folders. If you’re experiencing these problems, uninstall the particular update that is causing the issue:

• Win7/Vista: Start > Control Panel > Uninstall a Program > View Installed Updates… find KB2412171 and remove it.
• WinXP: Start > Control Panel > Add/Remove Programs.  Make sure “Show updates” (at the bottom) is checked.  Find KB2412171 and remove it.

Hope this helps.