My Airtunes device is password protected and while connecting I get an "401 Unauthorized".
According to http://git.zx2c4.com/Airtunes2/about/ RTSP allows to use a password for connecting to streaming devices.
So the GUI should provide an option to enter a password. This PW will be used to connect to the Airtunes.
Hope it's clear what I mean, since my understanding of raop/rtsp is very limited.
Thank you for taking the time to report this. Unfortunately the Airtunes2 protocol is not available for RAOP streams using pulseaudio. There is experimental work in progress to get this implemented but at the moment this will not be accessible through stream2ip.
Please add additional information on where we need a password for streaming audio to your device.