When I use Zplayer for periods of over 10 minutes sometimes the music just stops and won't play until I go into the app and re-select a song and/or restart the app.
I've sent an email to the Dev about it and never got response.
The developer is aware. Unfortunately I did not make ZPlayer and have not experienced this same issue so I cannot comment on it. I presume that this will be fixed in a later update.