The SIM card inserted in this iPhone does not appear to be supported. The SIM card that you currently have installed in this iPhone is from a carrier that is not supported under the activation policy that is currently assigned by the activation serve

That means the iPhone is locked to a carrier that is different to the one the sim card is for.

You need to contact the carrier it is locked to, and request they unlock it.

See here for details: How to unlock your iPhone for use with a different carrier - Apple Support

The only one who can unlock the phone is Sprint. Apple cannot help you. You have to deal with Sprint.

It means your iPhone is locked to a specific cellular service company, and the sim card you are trying to use is not from that cellular service company.

You need to either have the iPhone unlocked so it can use sim cards from other companies, or get a sim card from the company the iPhone is locked to.

Follow the steps here to unlock your iPhone: How to unlock your iPhone for use with a different carrier - Apple Support

mohammadAjaber wrote:

sim not valid

The "sim not valid" error means there's an issue with your sim card. Not necessarily that your iPhone is locked to a particular carrier.

See here :If you get an alert about the SIM card in your iPhone - Apple Support

I received the error and found that my iPhone is locked to Sprint, however I never had a Sprint account (I used a small, independent carrier called Ting) and they cannot unlock my phone. No one seems to be able to unlock it. What are my options? Can Apple do something on their end? Apparently my phone was assigned Sprint via a flex activation policy when I inserted a Sprint SIM card for use with Ting because they used Sprint's networks. But Sprint can't unlock and Ting can't either (they neither lock nor unlock phones, ever). I bought the iPhone 7 new from Best Buy and own it outright, but cannot use it (we get zero Sprint coverage in the area we just moved to). Help!

Sprint cannot unlock it because I never had an account with them (their words). They have no tools on their end to do it unless I create an account and pay for service for two months. I've spoken to 3-4 people at Sprint, supervisors, etc., all the same answer. It's a Flex Activation Policy between Best Buy and Apple that assigned it to Sprint. That answer, apparently, is in no man's land. Thanks, though!

This is the issue with buying a phone from Best Buy. Best Buy does NOT sell unlocked phones. ONLY Apple sells fully unlocked phones. Phones sold by Best Buy may not be locked in the box, but the moment you put in a Sim card, they lock, which in your case locked you to Spring via Ting. If this is the case, you either can get someone on the Ting side to help you, or you'll need to sell the phone and buy one fully unlocked. If Best Buy told you you were purchasing an unlocked phone, you may have some recourse with them as well. Otherwise, none of us users have any way to help you and as I mentioned earlier, neither does Apple.

Get a sim card from the carrier the phone is locked to or request that the carrier unlock the phone.

sim not valid

Then your phone is locked to a different carrier. Get a sim card from the carrier your phone is locked to.

Already answered this in the other thread you started. Posting again won't get you a different answer.