IMEI not comparable with my SIM card

If you see No Service or Searching on your iPhone or iPad

1. Check your coverage area. Make sure that you're in an area with cellular network coverage. ... 
2. Restart your iPhone or iPad. Restart your device. ... 
3. Check for a Carrier Settings update. ... 
4. Take out the SIM card. ... 
5. Reset your Network Settings. ... 
6. Update your iPhone or iPad. ... 
7. Contact your carrier. ... 
8. Get more help.

If you see No Service or Searching on your iPhone or iPad ...

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.

Carrier Lock:- Request your iPhone’s original Carrier to unlock your iPhone and if they agree and do it, then you may know the further process here --> How to unlock your iPhone for use with a different carrier ...

Device Unlocking Policies | Verizon Privacy Policy

Unlock a Phone or Device - AT&T Device Unlock Portal

Unlocking your Sprint device - T-Mobile

IMEI not compatible? Who said that to you?