Fix ChatGPT login failed fast by resetting the OpenAI session, allowing auth cookies/redirects, and removing extensions/VPN/DNS rules that break sign-in. Includes a cause-vs-fix table, browser-specific steps, and advanced fixes like HSTS/cache resets and corporate filtering checks.
ChatGPT login error 403 is almost always a block—not a bad password. This 2026 guide gives a fast checklist plus deeper browser, DNS, and work-network fixes (including advanced cache and TLS/inspection edge cases) to get you signed in quickly.
ChatGPT route error 500 on login after an update is most often caused by stale cookies/storage, a service worker cache mismatch, or an extension/VPN/proxy blocking the auth redirect. Use this fast checklist plus advanced cache/DNS/TLS fixes to restore login quickly.