Cursor auth

OAuth Token Refresh Fails After Cursor AI Refactor

After using Cursor's AI to refactor authentication code, OAuth token refresh requests return 401 Unauthorized errors. The application was previously handling token refresh correctly, but the AI-generated changes broke the flow.

Users are unexpectedly logged out during their sessions, and the app fails to silently refresh expired tokens before making API requests.

Error Messages You Might See

401 Unauthorized Invalid refresh token token_expired refresh_token_revoked
401 UnauthorizedInvalid refresh tokentoken_expiredrefresh_token_revoked

Common Causes

  1. AI generated incorrect token expiry comparison logic (using < instead of > or vice versa)
  2. Refresh token endpoint URL was modified incorrectly during refactoring
  3. Missing token type validation (Bearer token prefix stripped)
  4. Async/await chain broken, causing refresh to complete after API call
  5. Removed token storage in localStorage/sessionStorage during cleanup

How to Fix It

Verify the token expiry check uses correct comparison: Date.now() > expiryTime. Check that refresh endpoint matches OAuth provider docs. Ensure Bearer prefix is preserved. Validate token refresh completes before making authenticated requests.

Real developers can help you.

Stanislav Prigodich Stanislav Prigodich 15+ years building iOS and web apps at startups and enterprise companies. I want to use that experience to help builders ship real products - when something breaks, I'm here to fix it. Richard McSorley Richard McSorley Full-Stack Software Engineer with 8+ years building high-performance applications for enterprise clients. Shipped production systems at Walmart (4,000+ stores), Cigna (20M+ users), and Arkansas Blue Cross. 5 patents in retail/supply chain tech. Currently focused on AI integrations, automation tools, and TypeScript-first architectures. AUXLE AUXLE I am a Full Stack Developer experienced in building Websites, Web apps and Cross Platform Mobile Apps for Startups and Companies. Anthony Akpan Anthony Akpan Developer with 8 years of experience building softwares fro startups rayush33 rayush33 JavaScript (React.js, React Native, Node.js) Developer with demonstrated industry experience of 4+ years, actively looking for opportunities to hone my skills as well as help small-scale business owners with solutions to technical problems Victor Denisov Victor Denisov Developer Yovel Cohen Yovel Cohen I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well. Mehdi Ben Haddou Mehdi Ben Haddou - Founder of Chessigma (1M+ users) & many small projects - ex Founding Engineer @Uplane (YC F25) - ex Software Engineer @Amazon and @Booking.com Caio Rodrigues Caio Rodrigues I'm a full-stack developer focused on building practical and scalable web applications. My main experience is with **React, TypeScript, and modern frontend architectures**, where I prioritize clean code, component reusability, and maintainable project structures. I have strong experience working with **dynamic forms, state management (Redux / React Hook Form), and complex data-driven interfaces**. I enjoy solving real-world problems by turning ideas into reliable software that companies can actually use in their daily operations. Beyond coding, I care about **software quality and architecture**, following best practices for componentization, code organization, and performance optimization. I'm also comfortable working across the stack when needed, integrating APIs, handling business logic, and helping transform prototypes into production-ready systems. My goal is always to deliver solutions that are **simple, efficient, and genuinely useful for the people using them.** Matt Butler Matt Butler Software Engineer @ AWS

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Frequently Asked Questions

Why does my app work in dev but fail in production?

Token expiry times differ between environments. Ensure server time is synced and expiry buffer is adequate (refresh 30s before actual expiry).

How do I debug token refresh?

Add console.log statements before/after refresh call. Check network tab in DevTools for actual refresh request and response.

Related Cursor Issues

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