Fix: Claude Verification Code Not Sending

Claude uses temporary verification codes (One-Time Passwords or OTPs) sent via email or SMS to verify your identity during sign-up and login. If you are not receiving these codes, it blocks you from accessing your account. This troubleshooting guide helps you identify why the codes are failing and how to bypass the issue.

Troubleshooting email verification codes

If you log in via email and the magic link or verification code does not arrive in your inbox, try these steps:

1. Check Spam/Junk folders: Email filters often flag automated sign-in links. Check your Spam, Junk, Promotions, and Updates folders.
2. Search for the sender: Use your email provider's search bar to search specifically for mail from noreply@claude.ai or no-reply@anthropic.com.
3. Whitelist Anthropic domains: Add claude.ai and anthropic.com to your safe senders list or email contacts to prevent future filtering.
4. Avoid rapid resend requests: Clicking "Resend Link" multiple times in rapid succession can invalidate previous codes and trigger rate-limiting blocks on your IP address. Wait 5 full minutes between attempts.
5. Check corporate firewall settings: If you are using a work, university, or corporate email address, automated login emails are frequently blocked at the gateway level. Contact your IT administrator or register with a personal email account.

Troubleshooting SMS verification codes

If you are verifying your phone number during sign-up and the SMS OTP does not arrive, use the following methods to resolve the issue:

1. Verify your country code: Ensure you selected the correct country code from the dropdown menu and did not manually type the country code again in the phone number field.
2. Remove leading zeros: In many regions (such as the UK or Europe), you must omit the starting "0" of your phone number when entering it alongside the country code. For example, if your number is 07123456789, enter it as 7123456789.
3. Disable VoIP numbers: Claude does not allow the use of virtual phone numbers (VoIP) like Google Voice, Skype, Zoom, or online burner numbers due to spam prevention policies. You must use a valid SIM card from a physical mobile carrier.
4. Turn off spam filtering apps: If you use call/SMS blockers (such as Truecaller, RoboKiller, or built-in Android/iOS spam filters), temporarily disable them. These apps often misclassify OTP shortcodes as spam.
5. Check network signals and roaming: Ensure your mobile device has active cellular reception. SMS verification codes sent from international shortcodes cannot be delivered over weak Wi-Fi or when your device is on national/international roaming without an active SMS roaming plan.

Alternative login workarounds

If you continue to experience verification issues with manual email or SMS entry, bypass the OTP system by using federated login options:

• Google Sign-In: If your Claude account email is a Google/Gmail address, click Continue with Google. This bypasses Anthropic's email verification link entirely, authenticating you directly through your Google account.
• Apple Sign-In: If you have an Apple ID linked to your email, use the Continue with Apple button to log in securely without waiting for an OTP.

When to escalate

If you are using a physical, non-VoIP SIM card and have tried multiple times over 24 hours but still receive errors like "Invalid phone number" or "Failed to send verification code," contact support. Reach out through the Support widget on the Claude sign-in page or email support@anthropic.com. Provide your mobile operator's name, your country, your full phone number including the country code, and the email address you are attempting to register.