Within the past few days I'm unable to get to the dashboard on my Unraid server.  Normally I have the dashboard logged in and pinned in my browser but when I came back from a vacation recently going to that tab shows I'm on the dashboard page (http://10.0.0.97:180/Dashboard) but it's just a black screen. 

 

I tried opening and logging in via both Edge and Chrome browsers however when I enter my username and password I don't get a wrong credentials error, the tab only briefly 'thinks' for a second and then drops me back at the login screen again.  Even though I can't login my Plex server that runs on it is still available.

Try using a different browser, if the same get the diagnostics from the CLI then reboot the server by typing reboot.