SIM Support
Please my iPhone 5s does not support my current SIM card. Any help
Question marked as
Why not? What happens when you insert the SIM card exactly?
If you get the dreaded "Sim not supported" message, it means the iPhone is locked to a service provider that is different to the one the SIM card you inserted is for. Only the servicer provider it is locked to can unlock it.
click here ➜ How to unlock your iPhone for use with a different carrier - Apple Support
If something else is happening, please explain in as much detail as possible.