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How can I unlock my iPhone sim service provider manually?
How can I unlock my iPhone sim service provider manually?
That iPhone is probably locked to a different carrier and you can't unlock it "manually".
You need to contact the carrier which that iphone is locked to, and ask them to unlock it (if eligible).
See also this support article:--> How to unlock your iPhone for use with a different carrier - Apple Support
Regards
Giulio
Start here: https://support.apple.com/en-us/HT201328
Sim not valid