I had the same problem. When going to Setting on HA app, Settings were visible but via browser I would get the error “Error while loading page dashboard.”
@ khvej8 thanks for this tip, I tried it using Firefox and it worked for me.
I had to look this up and for anyone else who is curious:
F5 or Ctrl + R: Reloads page
Ctrl + F5 (Shift + F5) or Ctrl + Shift + R: to reload the current page, ignoring cached content.