This issue started today where on occasion just signing into AGOL via web browser or through the Navigator for ArcGIS app, we will get this error. Then it mysteriously goes away. I contacted our guy that works with ADFS and he said that he doesn't see any issues or errors on our end. But there seems to be an issue going on between our enterprise identity provider and AGOL's Portal for ArcGIS.
Is anyone else experiencing this issue recently where it was working normally beforehand?