Cellular data not working after wiping data and flashing stock rom

I have Ulefone S7 and cellular data doesnt work after wiping all data and factory reset because i flashed the stock rom from the manufacturer site. Wifi works fine but i get Nvram warning error 0xx10. Apn settings are correct for my provider. For some reason when i was on vacation on a diffrent place from that im living , cellular data worked perfectly fine. On every other place i have been ,i wasnt able to get it to work . One last thing, i got it to work randomly also when i used an app called DNS changer, but only for some seconds and then it did stop working again… i rooted the phone at first and then i removed the root but i still have the same issue… did i wiped some data that i shouldnt have?? …….pls help me solve this problem that im having for the last month