Network country lock

Hi! This most likely means that your iPhone is SIM locked. To check, go to Settings > General > About > Carrier Lock. It will most likely be assigned to a single carrier, the one you bought it from. If that’s the case, you would have to contact that carrier to ask if they can remove the Carrier Lock. Carrier Lock (or SIM lock) means that the iPhone is only allowed on the network that it was bought from (example: Telus or AT&T).

That message says nothing about country. The phone is locked to a carrier. You must contact that carrier and ask about their unlocking policy, as SlothMan1 says.