I just ran into this the second time recently. I was working in the Operations Manager console and everything was functional, but an error message occurred saying “The request failed with HTTP status 401: Unauthorized” (an example is shown below – the top line will vary depending upon which report folder it was attempting to open). In both cases, my password had been changed and I had not yet logged out of the Operations Manager console so what was happening is that my credentials were failing when it attempted to open the reporting pane.
Summary: Error accessing reports when the account password has changed.
Solution: Log out of the machine you are running the Operations Manager console on, log back in, re-start the Operations Manager console and re-open the Reporting pane.