Setting up a new IPhone
I succeeded in transferring my data from my old iPhone to the new one but it’s not recognizing my SIM card. What’s the problem?
iPhone 6, iOS 12
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Remove your 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.
If you see 'invalid SIM' or 'no SIM' on your iPhone or iPad ...
Learn what to do if you see a SIM not supported alert.
To be able to use any SIM across the globe you must have "No SIM Restriction" against Network Provider Lock. Please refer to the pic below.