Sometimes the webradio hangs or drops out despite an internet connection.
Volumio/mpd doesnt do a very good job at detecting this unfortunately. So it will sit there as if everything is still working.
I'd suggest implementing a similar logic as mpd-watchdog and check if the stream is still progressing.
the "seek" attribute in volumio status might be a good indicator.
Not sure if the attribute is reliably mirroring what MPD is doing, though.