Fix Claude SMS Verification Code Not Sending

Why Claude SMS Verification Codes Fail

Anthropic requires phone number verification during registration and occasionally during login to prevent bot spam and platform abuse. If you are not receiving the verification SMS, the problem is usually caused by cellular carrier filtering, strict regional blocks, or the use of unsupported phone number types (such as virtual or VoIP numbers).

Because Claude relies on third-party security vendors to deliver these SMS messages, standard delivery pathways can sometimes be delayed or filtered out as spam.

How to Fix Claude SMS Verification Issues

1. Confirm Your Number Type is Supported Anthropic does not allow all phone number types for account creation. To secure the platform, several categories are automatically blacklisted: * **VoIP Numbers:** You cannot use Google Voice, Skype, Twilio, or other virtual phone numbers. * **Prepaid/Burner Phones:** Some prepaid networks are flagged as high-risk and blocked. * **Landlines:** The system cannot deliver text codes to landline numbers.

You must use a standard, contract-based mobile phone number from a major cellular provider.

2. Format Your Phone Number Correctly Incorrect number formatting will cause the SMS routing protocol to fail. * Ensure you have selected the correct country code from the dropdown flag menu. * Omit the leading zero if your country's dialing rules require it for local calls (for example, in the UK, change "07123..." to "7123..."). * Do not include spaces, dashes, or special characters in the text input box unless the system formats it automatically.

3. Check for Carrier-Level Spam Filtering Mobile carriers frequently block automated text messages from short codes (short 5- or 6-digit phone numbers) to protect users from spam. * **Spam Folder:** Check if your phone has a "Spam and Blocked" folder in its messaging app (especially common on Google Messages for Android and iOS Message filtering). * **Short Code Blocking:** Contact your mobile carrier to verify if "Short Code Messaging" is disabled on your account. Ask them to enable or unblock automated messages.

4. Clear Browser Cookies or Switch Networks Local connection glitches can prevent the script that triggers the SMS gateway from executing properly. * Switch your device from Wi-Fi to cellular data (or vice versa) to rule out network routing delays. * Clear your mobile or desktop browser cache, or attempt the verification process using an Incognito/Private window.

5. Observe Rate Limits and Wait If you repeatedly click "Resend Code," the system will place a temporary rate-limit lock on your IP address and phone number. * If you have requested a code more than three times, stop. * Wait at least 15 to 30 minutes before requesting a new code to allow the automated cool-down period to expire.

When to Escalate

If you are using a legitimate, contract-based mobile number from a major carrier, have cleared your cache, and have waited 30 minutes without receiving a code, the delivery route to your carrier is likely broken.

Since you cannot bypass this screen on your own, you must contact Anthropic's support team. Visit the Anthropic Support Center and file a ticket under "Account Access." Specify your mobile carrier, your country, and the exact phone number you are trying to verify so that support can manually review your verification attempt.