Fix: Stripe 'This phone number cannot be used for verification' with AI Agents

If you're building AI agents that need to create Stripe accounts, you've hit this wall: This phone number cannot be used for verification. Your agent fills out the form perfectly, reaches phone verification, and — rejected. This guide explains exactly what's happening and how to solve it with real SIM-backed numbers. Why Stripe Blocks Your Number Stripe performs carrier lookups against multiple databases before sending any verification SMS: LERG (Local Exchange Routing Guide) — The authoritative database of North American phone numbers NPAC (Number Portability Administration Center) — Tracks number porting between carriers Real-time HLR queries — Verify active network registration on the carrier side If your number comes back as voip or nonFixedVoip , it's rejected immediately. The code is never sent. Provider line_type returned Stripe result Twilio voip ❌ Blocked Google Voice voip ❌ Blocked Vonage voip ❌ Blocked TextNow voip ❌ Blocked AgentSIM mobile ✅ Passes Why Twilio/VoIP Numbers F