I added an admin password (and a user password) and could use it to see status and evidently get to the input and output configuration pages and even the emoncms setup page (although I made no changes).
But when I went to the enhanced graph and tried to load a previously saved graph it just asked for the password over and over and over.
I was able to use the password I had set to change the password (to 5 lower case letters) and had the same problem. With that password I was able to remove both passwords and then graphs worked fine again.
I’m using firefox 66.0.3 on linux