ERR_LOGIN_HANDLER_FAILURE on Next.js Locally

This article addresses the ERR_LOGIN_HANDLER_FAILURE error that occurs during local development with the Auth0 Next.js SDK. This error typically appears without a clear explanation in the console and prevents successful integration.

• Auth0 Next.js SDK
• Local Development

A misconfiguration in the initAuth0 function's cookie settings commonly cause the ERR_LOGIN_HANDLER_FAILURE error. The issue arises during local development when the browser expects a secure HTTPS connection, but the local environment runs on an insecure HTTP connection. If the cookie settings include secure: true, the browser rejects the authentication cookies because they are not being sent over an encrypted channel.

To resolve this issue, the cookie settings within the initAuth0 function must be adjusted for local development. The configuration should be reviewed to ensure it does not enforce a secure connection for local testing.

//.env.local

AUTH0_COOKIE_SECURE=false

For more detailed examples and documentation on cookie configuration for the Next.js SDK, refer to the official repository.