Common Issues auth

Login or Signup Not Working in My AI App

Users try to log in or create an account but nothing happens, they get an error, or they're stuck in a loop. This is one of the most common issues with AI-generated apps because auth involves multiple moving parts.

Error Messages You Might See

Invalid login credentials Email not confirmed User already registered Failed to fetch 401 Unauthorized Redirect URI mismatch
Invalid login credentialsEmail not confirmedUser already registeredFailed to fetch401 UnauthorizedRedirect URI mismatch

Common Causes

  • Auth provider (Supabase, Firebase, Auth0) is not properly configured
  • Redirect URLs are wrong — the app sends users to the wrong page after login
  • Session or token management is broken — users appear logged in but the app doesn't recognize them
  • Email confirmation is required but the emails aren't being sent
  • Row Level Security (RLS) policies are blocking access to user data

How to Fix It

  1. Open browser dev tools (F12) and check the Network tab during login — look for failed API calls
  2. Verify your auth provider's redirect URL matches your actual app URL
  3. Check if email confirmation is enabled and whether emails are being sent (check spam folder)
  4. If using Supabase, check RLS policies — they often block legitimate queries
  5. Make sure your auth provider's API keys are correct in your environment variables

Real developers can help you.

Dor Yaloz Dor Yaloz SW engineer with 6+ years of experience, I worked with React/Node/Python did projects with React+Capacitor.js for ios Supabase expert Omar Faruk Omar Faruk As a Product Engineer at Klasio, I contributed to end-to-end product development, focusing on scalability, performance, and user experience. My work spanned building and refining core features, developing dynamic website templates, integrating secure and reliable payment gateways, and optimizing the overall system architecture. I played a key role in creating a scalable and maintainable platform to support educators and learners globally. I'm enthusiastic about embracing new challenges and making meaningful contributions. 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.** Pratik Pratik SWE with 15+ years of experience building and maintaining web apps and extensive BE infrastructure Matthew Butler Matthew Butler Systems Development Engineer @ Amazon Web Services 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 Meïr Ankri Meïr Ankri Full-stack developer specializing in React / Next.js / Node.js with 6+ years of experience. I've worked across various sectors including automotive (Reezocar/Société Générale), healthcare (Medical Link SaaS), and e-commerce (Glasman). I build web apps end-to-end, from architecture to production, with a focus on scalability, performance, and code quality. I also mentor junior developers and contribute to technical decisions and code reviews. 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. Antriksh Narang Antriksh Narang 5 years+ Experienced Dev (Specially in Web Development), can help in python, javascript, react, next.js and full stack web dev technologies. zipking zipking I am a technologist and product builder dedicated to creating high-impact solutions at the intersection of AI and specialized markets. Currently, I am focused on PropScan (EstateGuard), an AI-driven SaaS platform tailored for the Japanese real estate industry, and exploring the potential of Archify. As an INFJ-T, I approach development with a "systems-thinking" mindset—balancing technical precision with a deep understanding of user needs. I particularly enjoy the challenge of architecting Vertical AI SaaS and optimizing Small Language Models (SLMs) to solve specific, real-world business problems. Whether I'm in a CTO-level leadership role or hands-on with the code, I thrive on building tools that turn complex data into actionable value.

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Frequently Asked Questions

Users can sign up but can't log in. What's wrong?

Usually an email confirmation issue — check if your auth provider requires email verification. Also verify that the login redirect URL is correct.

Login works on localhost but not in production. Why?

Your auth provider's redirect URLs probably still point to localhost. Update them to your production domain in the auth provider's dashboard.

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