ATT sim unlock code?

[Android Central Question]

I'd bought an unlocked Nexus 6 from Ebay, decided to go prepaid with ATT.(Gophone). They could give me what I wanted, so I switched carrier. But now I have an ATT sim lock on my phone, T-Mobile sim won't recognize my device. Can anyone help me with an ATT's sim code? Or a PUK code?

 

[Rukbat]

No, you have to get the unlock code from AT&T - while the phone is on an AT&T plan (or GoPhone).