Step-by-Step Fix
1. Use Only the Most Recent Code
If you requested verification codes multiple times, all older codes are now invalid. Only the last code you received will work.
- Go to your email inbox
- Find the most recent email from Anthropic
- Ignore all earlier codes in previous emails
2. Enter the Code Within 2 Minutes
Claude verification codes expire within 10 minutes, but entering them within the first 2 minutes avoids edge cases with server clock differences and network delays:
- Request the code
- Switch to your email immediately
- Open the code email
- Return to the Claude verification page
- Enter the code within 2 minutes of receiving it
3. Type the Code Manually — Do Not Copy-Paste
Copy-pasting from email apps frequently introduces invisible whitespace characters:
- Open the email and read the code
- Click into the verification field on Claude
- Type each digit or character individually
- Double-check each character before submitting
4. Use a Single Browser Tab
Having multiple tabs open with the Claude login page can create session conflicts. The backend may associate the verification code with a different tab's session than the one you are completing.
- Close all Claude tabs except one
- Reload that single tab
- Start the login process fresh in that one tab only
5. Complete the Entire Flow in Incognito Mode
Old cookies can interfere with the verification session:
- Open an incognito or private window
- Go to claude.ai
- Start the login process from the beginning
- Request a new code (in this new session)
- Enter the code manually within 2 minutes
- Do not open additional tabs during this process
6. Clear Cookies for claude.ai
In your regular browser (after the incognito test):
- Go to browser settings → Privacy → Cookies
- Search for claude.ai and anthropic.com
- Delete all stored site data
- Restart the browser
- Try the verification flow again
7. Switch Browser or Device
If a code continues to fail in one browser, try another:
- Chrome, Firefox, Safari, Edge each handle session cookies differently
- Try a completely different device — if it works on mobile, the issue is your desktop browser
8. Contact Support With the Error Message
If the code fails across multiple browsers, devices, and fresh sessions:
- Take a screenshot of the exact error message
- Note the time you requested the code and the time you entered it
- Go to support.anthropic.com
- Report the issue with the error text and timing information
Why This Happens
Claude's verification system issues time-limited, single-use codes tied to a specific login session. If the session data in your browser does not match the session the server issued the code for — which happens after refreshes, multiple tab openings, or cookie changes — the code will be rejected even if the digits are correct. The session state mismatch is the most commonly overlooked cause.
Common Mistakes to Avoid
- Using an older code after requesting a new one — only the most recent code is ever valid
- Copy-pasting from email — invisible whitespace characters cause validation failures
- Having multiple Claude login tabs open — session conflicts cause code rejection
- Waiting too long after receiving the code — entering it more than 10 minutes after issue guarantees rejection
- Refreshing the verification page after receiving the code — this may invalidate the session the code was issued for
FAQ
Q: Does Claude send verification codes via SMS or only by email?
Claude sends verification codes only by email. There is no SMS option. The code is sent to the email address associated with your Claude account. If you cannot access that email inbox, you will need to regain access to it before you can log in — Claude support cannot bypass email verification or deliver codes through an alternative channel. Check your spam folder and any email alias routing rules before contacting support.
Q: Why would the same code work on my phone but not my computer?
If a code works on one device but not another, the most likely explanation is a session conflict: the verification code was issued for the session on one device, and entering it on a different device causes a session mismatch. Always complete the full login process — from clicking the sign-in button to entering the code — within a single browser session on a single device. Starting on one device and finishing on another will cause rejection.
Q: Can I request a new verification code if I did not receive the first one?
Yes. Wait two minutes before requesting a new code — some email providers delay delivery. If the code still has not arrived, check your spam, junk, and promotions folders, then request a fresh code. When you request the new code, the previous one is immediately invalidated even if it had not expired yet. Only the most recent code will work.
Q: What if my email provider blocks emails from Anthropic?
Some corporate email systems and strict spam filters block transactional emails from new senders. Check with your IT team to whitelist emails from anthropic.com. If you cannot whitelist it immediately, try logging in with a personal email account instead (Gmail, Outlook, etc.) and then changing your Claude account email after successful login.
Q: Is there a limit to how many verification codes I can request?
Yes. Requesting too many codes in a short period triggers a rate limit that temporarily blocks new code requests. The limit is typically around 3 to 5 requests within 10 minutes. If you hit this limit, wait at least 30 minutes before requesting another code. During the wait, do not attempt any login actions — even loading the login page can sometimes reset the timer.
Related Issues
- Claude login not working
- Claude account access – session expired
- Claude email not received – account activation
Additional FAQ
Q: What is the fastest way to diagnose a login problem? The fastest diagnostic is to open an incognito or private browser window and attempt to sign in there. Incognito windows run without extensions and use fresh cookies, which isolates the two most common causes: a browser extension interfering with authentication, or corrupted session cookies. If login works in incognito, the issue is your main browser profile. If it still fails, the problem is your network, your account, or a platform-side incident.