Music Playback Failed

Having Kodi V17 running and using music from my NAS i get the error playback failed
As soon as i click on a song my Kodi hang for a minute a then tells me playback fails ( one or more items failed to play )
Where can i find my log file to check it? This problem occured overnight .
I can reach my Nas , everything is working fine exept my Music.Huh