Recently, I encouncered an error while playing music in Linux with pulseaudio. gstreamer would say "failed to connect: connection refused" no matter what software was being used to play the audio. The solution appears to be quite simple. In your software's options or preferences, change the gstreamer output engine to Pulseaudio Sink. ALSA will not work, as you will eventually get this error. Any other annoying errors with (mostly) simple fixes?