Cannot integrate with Next JS 15 (Cookie error)

[Michahide]

Environment

  System:
    OS: Windows 11 10.0.22631
    CPU: (16) x64 13th Gen Intel(R) Core(TM) i7-13620H
    Memory: 3.14 GB / 15.70 GB
  Binaries:
    Node: 22.11.0 - C:\Program Files\nodejs\node.EXE
    npm: 10.9.0 - C:\Program Files\nodejs\npm.CMD
    pnpm: 9.12.3 - ~\AppData\Local\pnpm\pnpm.EXE
  Browsers:
    Edge: Chromium (130.0.2849.68)
    Internet Explorer: 11.0.22621.3527
  npmPackages:
    next: ^15.0.3 => 15.0.3
    next-auth: 5.0.0-beta.25 => 5.0.0-beta.25
    react: 19.0.0-rc-66855b96-20241106 => 19.0.0-rc-66855b96-20241106

Reproduction URL

Describe the issue

[ Server ] Error: Cookies can only be modified in a Server Action or Route Handler. Read more: https://nextjs.org/docs/app/api-reference/functions/cookies#options

How to reproduce

use the signIn method in page.tsx like this

const session = await auth()
if (!session) {
    await signIn("keycloak")
}

Expected behavior

User would be redirected to login page

[github-actions]

We could not detect a valid reproduction link. Make sure to follow the bug report template carefully.

Why was this issue closed?

To be able to investigate, we need access to a reproduction to identify what triggered the issue. We need a link to a public GitHub repository. Example: (NextAuth.js example repository).

The bug template that you filled out has a section called "Reproduction URL", which is where you should provide the link to the reproduction.

• If you did not provide a link or the link you provided is not hosted on github.com outside of the next-auth organization, we will close the issue.
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What should I do?

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My repository is private and cannot make it public

In most cases, a private repo will not be a sufficient minimal reproduction, as this codebase might contain a lot of unrelated parts that would make our investigation take longer. Please do not make it public. Instead, create a new repository using the templates above, adding the relevant code to reproduce the issue. Common things to look out for:

• Remove any code that is not related to the issue. (pages, API Routes, components, etc.)
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I did not open this issue, but it is relevant to me, what can I do to help?

Anyone experiencing the same issue is welcome to provide a minimal reproduction following the above steps by opening a new issue.

I think my reproduction is good enough, why aren't you looking into it quickly?

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Useful Resources

• How to create a Minimal, Complete, and Verifiable example
• Bug report: Framework
• Bug report: Provider
• Bug report: Adapter