When starting the program, PMS connects to the MPD server specified in the $MPD_HOST and $MPD_PORT environment variables.
In order to create a full-text search index for fast searches,
PMS retrieves the entire song library from MPD whenever the library is updated,
and on every startup.
If your song library is big, the listallinfo command will overflow MPD's send buffer,
and the connection is dropped.
This can be mitigated by increasing MPD's output buffer size,
and then restarting MPD:
cat >>/etc/mpd.conf<<<EOF
max_output_buffer_size "262144"
EOF
/etc/init.d/mpd restart # or equivalent