Progressively enhanced forms not working (405: not allowed) when deployed on vercel

[timoclsn]

Link to the code that reproduces this issue

https://github.com/timoclsn/next-forms-app

To Reproduce

1. Visit examaple deployment: https://next-forms-app-beryl.vercel.app/
2. Disable JavaScript in browser
3. Submit the form

Current vs. Expected behavior

Submitting the p.e. form with JavaScript disabled doesn't work (405: not allowed).

This should work when deployed on Vercel.

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 23.1.0: Mon Oct  9 21:27:24 PDT 2023; root:xnu-10002.41.9~6/RELEASE_ARM64_T6000
Binaries:
  Node: 18.18.2
  npm: 9.8.1
  Yarn: 1.22.17
  pnpm: 8.9.2
Relevant Packages:
  next: 14.0.4-canary.11
  eslint-config-next: N/A
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.3.2
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

App Router

Additional context

This happens when deployed on Vercel. It works locally (in dev and production mode).

[stevenmunro]

I'm chiming in because I'm encountering the same problem and I'm keen to stay updated on this discussion. It's imperative that we resolve this swiftly. It's not just about catering to users without JavaScript enabled; it's also about ensuring the integrity of our code. There's a chance there's an issue with my code, and I want to address it promptly to avoid potential future complications.

[github-actions]

This closed issue has been automatically locked because it had no new activity for 2 weeks. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.