Why i can't upgrade my firmware?

[okniesutrisno]

ZF Model: ZB602KL
RAM: 3G
Firmware/APP Version: OPM1 WW_Phone-15.2016.1901.339-20190108
Frequency of Occurrence: Everytime
Rooted: No
APP Name:

I can't upgrade my firmware even though on release update is already got new upgrade?