We’re using federated security with Office 365 and everything was running swimmingly and then I started getting the following error when trying to synchronize security information:

“An unknown error occurred with the Microsoft Online Services Sign-in Assistant. Contact Technical Support.”

Great.  Very descriptive.  In the event viewer, you get a bit more detail:

GetAuthState() failed with -2147186688 state. HResult:0. Contact Technical Support.  (0x80048831)

If you do some searching, you’ll find that there are a couple of MSDN articles about this error.  In KB2502710 you’re told to reinstall sign in assistant.  This one requires a reboot.  In KB2517393 you’re told to make sure that your proxy settings are working correctly.  I’m not using a proxy and everything was set up right.

Rather frustrating and I couldn’t figure out what was going on.  What finally keyed me in was the error number being presented.  Rather than 80048800, which is listed in the second article, I was getting 80048831.  I did a quick search and found something that was seemingly unrelated here.  Could it really be so simple as the password having expired for my synchronization user?

Turns out, it was that simple.  Once the password was reset and reentered, everything worked great again.

Since this isn’t a user that humans use, I also don’t want the password to expire.  You can find the instructions for that (use Set-MsolUser –UserPrincipalName <user ID> –PasswordNeverExpires $true) here.