Activation issue

Based on your screenshot see the following Apple articles:

Wireless carrier support and features for iPhone in the United States and Canada

Wireless carrier support and features for iPhone in the United States and Canada - Apple Support

Set up cellular service on iPhone

Set up cellular service on iPhone – Apple Support (UK)

Welcome to the Apple Support Communities.

See:

• Correct the purchase date or expiration date for your AppleCare agreement - Apple Support
• Update your proof of purchase - Apple Support

Either way, you'll need to contact Apple Support.

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