Continue with nearby guides in the same topic to rule out adjacent causes faster.
If your ChatGPT 2FA code is not working, the most common cause is a device clock that is more than 30 seconds out of sync — TOTP authenticator codes are time-based and invalid if your device time is wrong. Enable automatic time sync on your device and regenerate the code. If that fails, use one of your backup codes to log in and then re-enable 2FA.
A ChatGPT CAPTCHA loop — where the CAPTCHA reloads immediately after you solve it — is almost always caused by a VPN IP flagged as a data center address or automation-like browser behavior. Disable your VPN, switch to a clean browser profile with no extensions, and stop rapid retries; this resolves the majority of CAPTCHA loops within 2 minutes.
ChatGPT email verification links expire within 10–15 minutes — if your link says 'expired' or doesn't work, request a new verification email immediately and use only the latest link. If the link redirects you back to the login page instead of verifying, open it in an incognito window and clear cookies for chat.openai.com and openai.com before retrying.
If ChatGPT's desktop app won't let you log in, sign out and clear the app's cached credentials, then reinstall the latest version — the app stores session tokens locally, and a corrupted token file is the most common cause of desktop login failures. If reinstalling doesn't help, check whether the same account works at chat.openai.com in a browser.
If ChatGPT login fails on your iPhone or Android, force-close the app and reopen it, then clear the app's cache (Android: Settings → Apps → ChatGPT → Clear Cache; iOS: offload and reinstall). If that doesn't work, check your mobile data or Wi-Fi connection — mobile network restrictions and VPN apps are the second most common cause of mobile login failures.
ChatGPT login errors affect roughly 3 methods: email/password, Google OAuth, and Microsoft OAuth — all routed through auth0.openai.com. The fastest fix is to delete all openai.com and auth0.openai.com cookies, then retry in a fresh browser window. If you see a redirect loop, corrupted session cookies are the cause in over 80% of cases. If you see 'email or password incorrect' but your credentials are right, you likely signed up via Google or Microsoft and have no direct password — use the SSO button instead.