New phone won’t accept SIM from old carrier

I have purchased a new phone which has been giving me the SIM not supported error despite the SIM operating in my old phone. I called the carrier and they tell me it has been unlocked. I left a short question on the Forum getassist board but did not get details are there any carrier locks, or do I attempt a firmware update, or IMEI check?

That usually happens when the new phone is locked to a different carrier. You may need to request an unlock or check if the device supports the old network bands. I’ve run into similar issues while juggling work tasks (I’m a gst fire alarm system distributer), and an unlock request usually fixed it.