I can’t activate my iPhone 4S

See -> If you can't activate your iPhone or iPad (Wi-Fi + Cellular)

If you can't activate your iPhone or iPad (Wi-Fi + Cellular) - Apple Support

The iPhone 4s does not support 4G or LTE. If your service provider decommissioned 3G or 2.5G (USA) in your area in order to build out 5G service, your phone will never activate. Likewise, if you put a 4G SIM card in your 4s, the 4s will likely not know how to interface with it.

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