My iPhone 11 Pro Max says NO SERVICE when I insert my SIM

If you get an alert that says Invalid SIM or No SIM Card installed, follow these steps.

1. Make sure that you have an active plan with your wireless carrier. 
2. Restart your iPhone or iPad.
3. Check for a carrier settings update. Go to Settings > General > About. If an update is available, you'll see a prompt to select OK or Update.
4. Remove your iPhone SIM card or iPad SIM card from the SIM card tray and then put the SIM card back. Make sure that the SIM tray closes completely and isn’t loose. If you use a SIM tray from a different model iPhone, iPad, or from another phone manufacturer, it might not fit properly.
5. Try using another SIM card. If you don't have one, go to your carrier's retail store and ask them to test with another SIM card. You might need to replace your SIM card.

If you still see an alert about your SIM card, contact Apple support.

Learn what to do if you see a SIM not supported alert.

Also make sure that your SIM isn't broken, when I had this, my sim turned out to be broken so my carrier send my a new one and that worked