AI Verification Guide

Does Claude (Anthropic) Block VoIP Numbers?

If you're trying to verify a Claude (Anthropic) account and aren't receiving the SMS code, it's likely because you are using a virtual number.

Service Status: BLOCKED
Common Error Message:
"Error sending code. Please try a different number."
Why this happens:

Claude (Anthropic) queries the telecom database (HLR Lookup) to identify the carrier associated with your phone number. If it returns as a "Non-Fixed VoIP" or "Virtual" number, the SMS gateway deliberately fails to send the text message to prevent fraud and spam. Requires Real SIM.

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How to bypass Claude (Anthropic) VoIP blocks?

Trying to find a "VoIP bypass" for Claude (Anthropic) is a common mistake. Verification systems provided by companies like Twilio or Vonage are extremely efficient at detecting virtual numbers. The block is enforced at the network level, not the app level.

To successfully receive a verification code for Claude (Anthropic), you need a number that is issued by a genuine Mobile Network Operator (MNO).

The SecondSIM Solution

SecondSIM provides you with an instant eSIM that operates on the UK's O2 and Three networks. Because these are standard consumer phone lines, Claude (Anthropic) cannot block them. They register perfectly during sign-up.

  • Not VoIP - Genuine Mobile Network Codes (MNC)
  • Guaranteed SMS delivery from all shortcodes
  • No hardware required - activates via eSIM in minutes