"GUI address overridden by startup options" (username/password)

Hello Forum,

Syncthing, respectively Synctrayzor, has just reported to me that I should assign a username and password, because otherwise hackers can access my files (or something like that).

I did do so, and now I get the message:

  • “The GUI address is overridden by startup options. Changes here will not take effect while the override is in place.”

What does that mean again, and what do I have to do to make my username/password combination take effect?