We ran the 9.1 upgrade on our 8.5.1 Orion NPM yesterday. It was not one of our better SolarWinds experiences. After significant effort, we got both of our polling engines running. System Manager comes up fine on both servers as well. However, we are still stuck with a down web console. When trying to access the web console, we get an error that says "Orion License Error. License check failed." This is on both the main Orion SLX web console and our additional web console (on a separate server). We opened a ticket on this (#63890) and spent several hours on the phone with support yesterday, but they eventually said they needed to get the development team involved.
It is probably too much to hope that anyone else has seen this error and has a fix, but I thought I'd throw it out here anyway. I'll post a follow up whenever the dev guys get around to looking at this.