auth() returns null in route handler when a user is signed in via Google

[JihongGan]

Environment

  System:
    OS: macOS 14.2.1
    CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
    Memory: 587.47 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.5.1 - /usr/local/bin/node
    Yarn: 1.22.22 - /usr/local/bin/yarn
    npm: 10.8.2 - /usr/local/bin/npm
  Browsers:
    Chrome: 128.0.6613.86
    Safari: 17.2.1
  npmPackages:
    @auth/unstorage-adapter: ^2.0.0 => 2.4.2
    next: latest => 14.2.7
    next-auth: beta => 5.0.0-beta.20
    react: ^18.2.0 => 18.3.1

Reproduction URL

https://github.com/JihongGan/next-auth-example

Describe the issue

In the example app's catch-all handler app/[...proxy]/route.tsx, auth() returns null even when a user is signed in via Google.

How to reproduce

1. Run the example app fork in the repro link following its readme
2. Sign in via Google at http://localhost:3000
3. Call the catch-all handler by visiting http://localhost:3000/foo
4. Observe that console logs error Authentication failed, since session is null

async function handler(request: NextRequest) {
  const session = await auth()
  if (!session) {
    console.error("Authentication failed");
  }
...
}

Expected behavior

session should not be null and console should not log the error message.

[apuntovanini]

Any news on this? @JihongGan did you manage to solve it?