Samsung Galaxy J5 2017 sim card problem

[Kameluszek]

Hi. I have Samsung Galaxy J5 2017 in o2 network, however phone doesn't see o2 new sim card. I tried to unlock the phone to another networks but codes doesn't work either. Is it anything in the settings I have to changed?Please help.

[BandOfBrothers]

If the phone is locked to o2 then it should just accept the o2 sim card. 

Is the sim card working i.e. activated  ?

Can you try it in another phone ?

If the phone is locked to another Network then that network would have to unlock it. 

Where did you get your "Codes" from ?

[kmasum]

Let say i don't have another mobile then what should I do?

[CarlH]

Have you gone through any troubleshooting steps or spoken with O2 regarding this, @Kameluszek?