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.
Don’t test on Linux, but I am able to recreate on Windows with Firefox. I get the problem when there is both an admin and a user password. There doesn’t seem to be a problem when there is only an admin password.
The password feature used is custom above and beyond what is available from the ESP8266 Arduino IDE web server. It attempts to support multiple users and two classes of password and TBH has never really worked as well as intended. The various browser support for digest authentication is a problem. In the future that will be scaled back to a single admin password and probably remove the user capability, which is of limited usefulness anyway.
The intention is to be able to revert to the supported authorization functions in the underlying web server. So bottom line, if you set just an admin password (leave the user blank) it should work OK and you should be OK going forward.
If you run into problems with that, please post the situation.