No widget available - can't use app

Issues
1

No widget available

Android 8.1.0

Device: Samsung J5 2016 (J510FN)

Rom: RR-O-v6.1.0-20180611-j5xnlte-Unofficial

Nova launcher 6.1.6 (works on another device with exactly the same launcher)

2

SOLVED

app has to be installed in internal memory