PiMusicBox web client reachable via PC by not mobile

I’ve been having intermittant issues with connecting to the default web client interface of piMusicbox via my mobile (standard android phone, using chrome). A lot of the time it works fine, but then others it just won’t connect to the pi, I’m left with the (cached I assume) client saying “Trying to reach MusicBox on…”

If I open the same address on my pc, which is cat5 connected to the network, it works fine. So the Pi is up and listening.

Anyone have an idea what could be going on?