3-5 min video crashing problem

Good Evening everyone, I’m writing this thread beacause I’m experiencing a very disappointing problem with my kodi 17 on ipad pro. Every time I start a video from my NSA zyxel325 the film starts but after 5 min it stops and goes back to the film list page, the same with tv series (in this case after 3 min). I’m connected to the NSA through SMB. Is there anyone that can help me to find out how to fix this please. Thank you for your time!