Motorola Moto G — moto g6 play sim network unlock pin

Hi, Im having trouble with my moto g6 play, i brought the phone about 4 months with a damage screen that i have finally replaced with a new one.

the problem im having now is the phone is asking for sim network unlock pin, i have no idea what network carrier its lock too, ive also emailed the previous owner

to ask what network its on about 2 months ago but i have not received a email back, i have tried the top 4 networks sims still no joy, ive checked the phones imei number

to see if its blocked or stolen and its not its all clear, so what im asking is how can i find out what network carrier this phone is locked too, or will i have to get hold of

as many pay as you go sim card from different network carrier and try one at a time.

i would appreciate any help

thanks