iPhone 7 - Carrier not supported
I bought an AT&T iPhone 7 from Bestbuy. Also checked it with lycamobile sim in USA- It worked. Hence I believe it is an unlocked phone. It was mentioned universal iPhone & i bought at full price too.
I have sent it to my brother in India. However It isnt working with indian Sim cards (Airtel, vodafone)
Error message shown - "Carrier not supported".
Could not figure out the reason why it doesn't work? Please help.
iPhone 7, iOS 10.0.2