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 calling auth0.updateSession(req, res, session) in a Page router endpoint, response header set-cookie is empty. And the session is never updated on the client.

'set-cookie': [ 'appSession=; Path=/; Max-Age=0' ]

Reproduction

In a Page API route add the following code.

let session = await auth0.getSession(req);
session.user.username = "younameit";
await auth0.updateSession(req, res, session);
console.log(res.getHeaders());

Additional context

No response

nextjs-auth0 version

4.9.0

Next.js version

15.5.2

Node.js version

20.18.0