Mopidy seems to crash - Where to start Analysis

Sometimes, after selecting an item in one the playlists (in browser), mopidy is not accessible any more. Neither via web interface nor via MPD.

In the web browser, I get no answer from 192.168.x.x:6680. In MPD clients I get no results back, but in /var/log/mopidy/mopidy.log it tells me something about new connections:

2015-11-24 21:56:15,107 INFO [25633:MpdSession-56] mopidy.mpd.session: New MPD connection from [::ffff:192.168.0.17]:58287
2015-11-24 21:56:25,621 INFO [25633:MpdSession-57] mopidy.mpd.session: New MPD connection from [::ffff:192.168.0.17]:58298
2015-11-24 21:56:36,114 INFO [25633:MpdSession-58] mopidy.mpd.session: New MPD connection from [::ffff:192.168.0.17]:58299
2015-11-24 21:56:46,612 INFO [25633:MpdSession-59] mopidy.mpd.session: New MPD connection from [::ffff:192.168.0.17]:58301
(and so on)

Of course,
service mopidy restart
helps, but that could not be the overall solution.

Where might I start for analysis. Is there a separate log file for the web server or for gstream(?) etc.?

https://docs.mopidy.com/en/latest/troubleshooting/ is a good place to start.