W: [pulseaudio] authkey.c: Failed to open cookie file '/home/user/.config/pulse/cookie': No such file or directory W: [pulseaudio] authkey.c: Failed to load authorization key '/home/user/.config/pulse/cookie': No such file or directory
I had this problem on an embedded box, with no X11, or even a screen. Turns out that at least some versions of Debian have an issue where not all programs agree on where the cookie file should be stored. Doing ls -la in my home directory revealed I had a ~/.pulse-cookie file, but I didn’t, as the warning message stated, have a ~/.config/pulse/cookie file.
I made this warning go away by symlinking where one program was looking for the cookie to where the cookie actually was.
mkdir -p ~/.config/pulse cd ~/.config/pulse ln -s ../../.pulse-cookie cookie
..and Bob’s your uncle. No more warnings.