What is the problem?
Recently both of my Octoprint installs have begun requiring Logins. This happens regardless of the platform (windows, IOS). This didn't used to happen, rather launching the browser would take me to the main screen.
What did you already try to solve it?
Not much other than to poke around in the setting menu to see if something there would help.
Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, octoprint.log, serial.log or output on terminal tab, ...)
I have the following versions: OctoPrint 1.3.10 running on OctoPi 0.15.1