debug log(wiki) and which osx version do you use ... and which xbmc version. Try to give some more info - how are we supposed to help if you only state that you are using xbmc?
AppleTV4/iPhone/iPod/iPad: HowTo find debug logs and everything else which the devs like so much: click here
HowTo setup NFS for Kodi: NFS(wiki)
HowTo configure avahi (zeroconf): Avahi_Zeroconf(wiki)
READ THE IOS FAQ!: iOS FAQ(wiki)