How to root ms550

Mode: Normal
Model: LGMS550A
Build version: Nov 30 201715:17:15Aug 09 201723:00:00LGMS550A
SW Version: MPSS.JO.1.2.c2.1-00028-8937_GENNS_PACK-1.109862.1
IMEI: 35987206038023-4
BlueTooth Address: 00:00:00:00:00:00
Phone Code:
Elapsed: 1 secs. --> (v9.48)

Checking Login and Password... OK
Ballance: 20 crd.
You have 20 credit(s) left. This operation takes 10 credits.Continue? Yes
Searching modem interface... found COM9
Reading data from phone... OK
IMEI: 359872060380234
Checking root rights... fail
Elapsed: 2 secs. --> (v9.48)