I would suggest running the Permission checker usually found in the program files\ solarwinds Orion \ Orion folder.
I've also noticed this while in Chrome. When it starts happening, I copy the url, kill the tab and open a new tab. Everything works for after that (for a while).
I would definitely call SolarWinds tech support and open a case on this one.
But you might try repairing your installs on your web server from the "Programs and Features" or "Add or Remove Programs" section of the Windows control panel. I'm note sure exactly which module you'd need repair, though. I typically repair Solarwinds Orion NPM, Solarwinds Core Services, and Solarwinds Information Service l when I have this type of issue.