Step-by-Step Fix
1. Try Incognito / Private Mode
- Open an incognito/private window
- Sign in again
2. Clear Cookies and Site Data
- Clear cookies/site data for the service
- Restart your browser
3. Disable Browser Extensions
Disable temporarily:
- ad blockers
- privacy/anti-tracking extensions
- script blockers
4. Switch Browser or Network
- Try another browser (Chrome/Safari/Edge)
- Try mobile hotspot to rule out network filtering
5. Re-authorize Google/Apple Login (If Used)
- Log out
- Start the login flow again
- Complete the OAuth prompt fully
6. Check for Outages
If there’s an outage, wait a few minutes and retry.
Why This Happens
Claude authenticates users through OAuth redirects handled by Google, Apple, or Anthropic's own magic-link email system. Login failures occur when a redirect is blocked (by a cookie policy, extension, or firewall), when a magic link expires (each link is valid for 15 minutes and single-use), or when the auth provider session itself is stale. The result is always the same from the user's perspective: the browser returns to the login screen without a clear error.
Common Mistakes to Avoid
- Clicking the magic link in a different browser than the one you started the flow in. If you open the login page in Chrome and the magic link email in Firefox, the session context doesn't carry over and the login fails. Always open the link in the same browser.
- Using a corporate email with a link-rewriting gateway. Many enterprise email systems rewrite URLs in emails for security scanning. This breaks single-use magic links because the rewritten URL is different from what Anthropic's server expects. Use a personal email or ask IT to whitelist anthropic.com links.
- Waiting too long before clicking the magic link. Magic links expire after 15 minutes. If you check your email after 20 minutes, request a new link rather than clicking the expired one.
- Not checking if the auth provider itself is down. If you log in with Google, and Google's OAuth service has an incident, no Claude-side fix will help. Check downdetector.com for Google outages before troubleshooting locally.
- Forgetting which login method you used originally. Trying to log in via email when you originally signed up via Google creates a new separate account. Always use the same auth method you used at signup.
Q: Why does Google login work on mobile but not desktop? Desktop browsers often have stricter pop-up and cookie policies than mobile browsers, especially if you have extensions installed. Google OAuth opens a pop-up window for consent; if your desktop browser blocks pop-ups for claude.ai, the authentication fails silently. Allow pop-ups for claude.ai in your desktop browser settings and retry.
Q: Can I change my login method from Google to email without losing my account? This requires contacting Anthropic support. Account recovery and login method changes are handled manually with identity verification. You cannot change your auth provider through self-service settings. Provide your original Google account email and any billing receipts to support to verify ownership.
Q: What does "Authentication failed" mean specifically? It means the auth server rejected the credential or redirect token. Common triggers: expired magic link, mismatched CSRF state (caused by using two browser tabs), or an IP address flagged for suspicious activity. Try from a different network and a fresh browser session before contacting support.
Q: Is there a way to log in without email access? If you use Google or Apple login, you can log in through those providers without needing access to your email for a magic link. If your account is email-only and you've lost access to that email, contact Anthropic support with billing receipts or other account verification as your only recourse.
Q: My account shows as logged out every time I restart the browser. How do I fix this? Your browser is not persisting the Claude session cookie. Check your browser settings for "Clear cookies on close" or "Never remember history" mode—both will delete your session on every restart. Disable these settings for claude.ai, or add claude.ai to your browser's cookie whitelist. Also check if your security software is clearing browser data on exit.
Related Issues
- Claude login & access hub
- Claude login not working or verification loop
- Claude login page not loading
- Claude redirected back to login page
- Claude workspace access denied
- Claude access issues after switching devices
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.
Q: Why does clearing browser cache fix login issues? Your browser caches session tokens and authentication cookies that prove you are logged in. If these become corrupted or expire mid-session, the browser may present an invalid token on each page load, causing the server to reject the session and redirect you to login. Clearing site-specific data forces the browser to request fresh tokens on the next login, which resolves most session-related loops without affecting your other browser data.
Q: Should I try a different browser if login keeps failing? Yes — testing in a second browser is one of the most useful steps. Different browsers use different cookie stores, extension ecosystems, and caching mechanisms. If login works in Browser B but fails in Browser A, the issue is specific to Browser A's state (likely extensions or corrupted profile data), not your account. You can continue working in Browser B while you troubleshoot the original browser.
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- Claude usage limit reached
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- Claude blank page white screen
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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.
Q: Why does clearing browser cache fix login issues? Your browser caches session tokens and authentication cookies that prove you are logged in. If these become corrupted or expire mid-session, the browser may present an invalid token on each page load, causing the server to reject the session and redirect you to login. Clearing site-specific data forces the browser to request fresh tokens on the next login, which resolves most session-related loops without affecting your other browser data.
Related Articles
- Claude usage limit reached
- Claude rate limit fix
- Claude blank page white screen
- Claude can't log in fix
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.
Related Articles
- Claude usage limit reached
- Claude rate limit fix
- Claude blank page white screen
- Claude can't log in fix
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.