Facing the same issue, I'm using firebase via next-firebase-auth-edge.

The issue happens only on production deployments on vercel, for example it doesn't happen when I make a production build locally.

Even though my logs are full of Error 500:

Error: Cannot find module 'undici'

And in the devtools network panel i see

But the page is served properly and functioning as expected!

I don't know if this should be reported for firebase, vercel, or nextjs! but I'm gonna report it on every repo to make sure it gets the needed attention.

If it helps anyone, here's the require stack displayed with the error:

Error: Cannot find module 'undici'
Require stack:
- /var/task/apps/web/.next/server/app/(logged-out)/signup/page.js
- /var/task/node_modules/.pnpm/[email protected]_@babel [email protected]_@opentelemetry [email protected][email protected]_react-dom@1_w5bu2sx7by3sz6f3kfihanbzuu/node_modules/next/dist/compiled/next-server/server.runtime.prod.js
- /var/task/apps/web/___next_launcher.cjs
- /opt/rust/nodejs.js
    at Module._resolveFilename (node:internal/modules/cjs/loader:1145:15)
    at /var/task/node_modules/.pnpm/[email protected]_@babel [email protected]_@opentelemetry [email protected][email protected]_react-dom@1_w5bu2sx7by3sz6f3kfihanbzuu/node_modules/next/dist/compiled/next-server/server.runtime.prod.js:11:28979
    at Module._load (node:internal/modules/cjs/loader:986:27)
    at /opt/rust/nodejs.js:1:11508
    at Function.Wt (/opt/rust/nodejs.js:1:11878)
    at Q.e.<computed>.K._load (/opt/rust/nodejs.js:1:11478)
    at Module.require (node:internal/modules/cjs/loader:1233:19)
    at u.require (/var/task/node_modules/.pnpm/[email protected]_@babel [email protected]_@opentelemetry [email protected][email protected]_react-dom@1_w5bu2sx7by3sz6f3kfihanbzuu/node_modules/next/dist/compiled/next-server/server.runtime.prod.js:11:29195)
    at _require.i.require (/var/task/apps/web/.next/server/chunks/1161.js:22:66784)
    at require (node:internal/modules/helpers:179:18) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [
    '/var/task/apps/web/.next/server/app/(logged-out)/signup/page.js',
    '/var/task/node_modules/.pnpm/[email protected]_@babel [email protected]_@opentelemetry [email protected][email protected]_react-dom@1_w5bu2sx7by3sz6f3kfihanbzuu/node_modules/next/dist/compiled/next-server/server.runtime.prod.js',
    '/var/task/apps/web/___next_launcher.cjs',
    '/opt/rust/nodejs.js'
  ],
  digest: '1496355909'
}

Thank you for bringing this to our attention. I tried implementing firebase via next-firebase-auth-edge but I wasn't able to experience any error 'Cannot find module undici'. Aside from Auth, are you using any other Firebase products? Also, I noticed a similar issue filed in Vercel repo. Does rolling back the version to 14.1.4 works on your end?

I have the same issue. Page loads fine but the first load is always a 500 which is poluting the logs.
I'm on Next.js v14.3.0-canary.24

@SaizFerri Can you test rolling back your version as mentioned above by @jbalidiong?

@DellaBitta Issue is that I need at least v14.3.0-canary.24 as that version introduced a critical fix to how cookies are set in the middleware, which I also need for auth. :/

Still, if we can pinpoint exactly which version things started to go wrong then we can bring the support case to the Next.js team and ask them what the problem might be.

@DellaBitta I see what you mean but that app is running on production so I can't easily downgrade the Next.js version there. I can try on our dev env and keep a look at the logs.

Hi @SaizFerri,

that would be very helpful since we can't reproduce it ourselves. Thanks!