At some point within the past couple days our Enterprise logins have stopped working with ArcGIS Online. I'm not really sure if it's on our end, some configuration within AGO that needs to be updated since the latest AGO update, or what exactly.
The setup for using enterprise logins has not changed within our AGO settings since initially configured.
Below is a screenshot of the error we get when trying to use our enterprise logins. Perhaps this means something to someone and we can be pointed in the right direction, or give our IT group some ideas of where to look.