Solved! Go to Solution.
I've found a solution that works with my phone, Galaxy S6
This weekend I found out that not only Spotify stops after playing some 5 numbers, but also my other musicplayers. Even when I play music with Firefox it stops after a few songs. So a new search on the internet to solve this problem began.
I've found that my S6 automatically saves batterylife and that that might be the problem. Go to your settings, battery, App optimalisation, Details. Go to Spotify or other musicplayers and turn of App optimalisation.