Checklist

• The issue can be reproduced in the nextjs-auth0 sample app (or N/A).
• I have looked into the Readme, Examples, and FAQ and have not found a suitable solution or answer.
• I have looked into the API documentation and have not found a suitable solution or answer.
• I have searched the issues and have not found a suitable solution or answer.
• I have searched the Auth0 Community forums and have not found a suitable solution or answer.
• I agree to the terms within the Auth0 Code of Conduct.

Description

When @auth0/nextjs-auth0 is upgraded to v4.17.0, it breaks.

This is @auth0/nextjs-auth0 used in the front-end.

import { Auth0Client } from '@auth0/nextjs-auth0/server'

export const auth0 = new Auth0Client({
  authorizationParameters: {
    audience: 'https://testAPI/',
    scope: 'openid profile email',
  },
})

And this is the backend.

export const GET = auth0.withApiAuthRequired(async function (
  request,
  { params },
) {
...
}

When being upgraded to v4.17.0, auth0.withApiAuthRequired returns 401 with { "error": "not_authenticated", "description": "The user does not have an active session or is not authenticated" }. It works well on v4.16.2

analysis

The cookie on the latest version of auth0 becomes:

__session_0: ...
__session_1: ...

Looking forward to the solution.

Reproduction

Just upgrade to v4.17.0.

Additional context

No response

nextjs-auth0 version

4.17.0

Next.js version

16.2.3

Node.js version

25.9.0