Sony xperia z3 compact - what is that? - nano sim doesnt work

[Ghroul]

I just bought a z3 compact for a friend and we dont know what is the white thing over the nano sim.

Another issue we found (its mostly a problem) is that the phone doesnt even recognise the nano sim.

[Phy]

The white thing is the IMEI number

http://support.sonymobile.com/global-en/xperiaz3compact/userguide/IMEI-number/

[Uliwooly]

@Ghroul

Is it a NANO SIM card or did you trimmed a regular SIM card?