Step-by-Step Fix
1. Stop and Clear the Stuck Session
Do not keep refreshing the stuck callback URL — this will not help. Instead:
- Navigate away from the stuck URL (go to google.com or another site)
- Open a new tab
- Do not close the browser yet
2. Clear Cookies for claude.ai
- Open browser settings → Privacy → Cookies
- Search for claude.ai, anthropic.com, and accounts.google.com (if using Google login)
- Delete all stored data for these domains
- Also clear any session storage (in Developer Tools → Application → Storage → Clear Site Data)
3. Try the Login in Incognito Mode
- Open a new incognito window (Ctrl+Shift+N on Chrome, Cmd+Shift+N on Mac)
- Go to claude.ai from the beginning — not the callback URL
- Click "Continue with Google" (or Apple)
- Complete the authorization
- Let the redirect complete without navigating away
If this works, the issue was your regular browser's cookies or extensions.
4. Disable Extensions That Block Redirects
Extensions that frequently cause callback failures:
- uBlock Origin — can block callbacks from Google/Apple domains
- Privacy Badger — blocks cross-site tracking (which OAuth callbacks resemble)
- HTTPS Everywhere — can interfere with redirect chains
- Cookie AutoDelete — may delete cookies mid-OAuth flow
Disable them all temporarily, then retry login in your regular browser.
5. Allow Third-Party Cookies (Temporarily)
OAuth flows require temporary cross-domain cookies. If your browser blocks all third-party cookies:
Chrome: Settings → Privacy and Security → Cookies → Allow all cookies temporarily → Retry login → Re-enable blocking after
Safari: Preferences → Privacy → Uncheck "Prevent cross-site tracking" → Retry → Re-enable after
Firefox: Settings → Privacy & Security → Custom → Uncheck "Cookies across websites"
6. Switch to a Different Network
If your network uses a proxy or firewall that intercepts HTTPS traffic, it can break the OAuth callback chain:
- Connect to a mobile hotspot
- Try the login from claude.ai
7. Use Email Login Instead
If Google/Apple login continues to fail, use email-based login:
- On the Claude login page, click the email option
- Enter your account email
- Check your email for the code
- Enter the code — this bypasses OAuth entirely
8. Contact Support With the Callback URL
If the issue persists in incognito on multiple networks:
- Copy the full URL you are stuck on
- Go to support.anthropic.com
- Report the issue including the callback URL, browser, OS, and what you already tried
Why This Happens
OAuth 2.0 login uses a state parameter to match the initial login request with the incoming callback. If the browser session that initiated the login (and stored the state) is different from the session receiving the callback — due to extensions clearing cookies, a new tab being opened, or session state being reset — Claude's server cannot verify the callback and the login fails. The browser ends up on the callback URL with no matching session to complete.
Common Mistakes to Avoid
- Refreshing the stuck callback URL — the callback URL is a one-time use token; refreshing it won't complete the login
- Starting a new Google/Apple auth while still on the callback URL — close the tab completely and start fresh from claude.ai
- Not disabling all extensions — disabling just one when multiple are installed may not solve the problem; disable all and re-enable one by one
- Using a browser that blocks all third-party cookies without exceptions — OAuth requires temporary cross-domain cookies; the strictest privacy settings break it
FAQ
Q: What does a "callback" URL mean and why does login get stuck there? When you click "Sign in with Google" or "Sign in with Apple," Claude sends you to Google or Apple's servers to verify your identity, then those servers redirect you back to Claude's callback URL (typically something like claude.ai/callback?code=...). Claude's server matches the incoming code with the original login request to confirm they belong together. If the browser session that started the login is no longer active — due to an extension clearing cookies, a new tab opening, or a session reset — the match fails and the callback URL goes nowhere, leaving you stuck.
Q: Is it safe to close the browser tab when stuck on a callback URL? Yes. Closing the stuck tab does not delete your account or cause any issues. The callback URL is a single-use, time-limited token that is effectively expired once you close the tab anyway. After closing, clear cookies, open a fresh browser window or private tab, and navigate directly to claude.ai to start a new login attempt from scratch.
Q: Why does this happen with Google login but not email login? Email-based login (entering your email and a code or password) uses a simpler flow that is less sensitive to session state changes. Google and Apple OAuth logins involve a redirect chain across multiple domains — claude.ai → Google/Apple → back to claude.ai — and each hop requires the browser to correctly handle cross-domain cookies and session state. Extensions that block third-party cookies or clear state between domain changes are more likely to break this multi-hop flow than a straightforward email login.
Q: Does this issue happen only with certain browsers? Browsers with strict privacy defaults are more prone to this issue. Brave Browser's shields, Firefox's Enhanced Tracking Protection in strict mode, and Safari's default cross-site tracking prevention all have settings that can interfere with OAuth callback flows. Chrome with minimal extensions has the fewest OAuth issues. If you must use a privacy-focused browser, temporarily reduce privacy settings for claude.ai specifically rather than disabling protection globally.
Q: My OAuth callback was working fine for weeks and suddenly stopped — what changed? Browser updates often change default cookie and storage settings without announcement. Extension updates can also add new blocking rules. If a previously working login flow suddenly breaks, suspect a recent browser or extension update. Open your browser's extension list and check "recently updated" extensions, then test in incognito (no extensions) to isolate the cause. A browser update changing third-party cookie defaults is a common trigger for this pattern.
Q: Can I stay logged in to avoid the callback issue entirely? Yes. The callback issue only occurs during the login process itself. Once logged in, Claude keeps you authenticated as long as your session cookie remains intact. Avoid clearing cookies or using browser cleaning tools that delete session cookies. Using "Remember me" or equivalent options if prompted, and not using private/incognito mode as your default Claude browsing mode, helps maintain a persistent login.
Prevention Tips
- Use email-based login (magic link or password) as an alternative to Google or Apple OAuth if callback issues recur — it uses a simpler flow with fewer failure points
- Add claude.ai to your browser's trusted sites or cookie exceptions list to prevent privacy settings from interfering with the OAuth flow
- If you use browser cleaning tools (BleachBit, CCleaner, browser built-in clear data), exclude claude.ai cookies from cleanup schedules
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.
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