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# React Router app deploys successfully but returns 500 error on access

151 views · 3 likes · 8 posts


Gregoryzeng (@gregoryzeng) · 2025-10-29 · ♥ 1

Hi team,
My React Router project recently **deploys successfully** on Vercel, but the deployed site shows a 500 error when accessed:
```
500: INTERNAL_SERVER_ERROR
Code: FUNCTION_INVOCATION_FAILED
ID: iad1::9mzx2-1761741964954-b9ba1575dd91
```

The server logs display this message:
```
Cannot find module '/var/task/node_modules/@mjackson/node-fetch-server/dist/node-fetch-server.cjs'
Did you forget to add it to "dependencies" in `package.json`?
Node.js process exited with exit status: 1. The logs above can help with debugging the issue.
```

However, this error occurs even though I haven’t changed anything related to dependencies. The latest code runs normally in my local machine.

To verify, I reproduced the issue using the official React Router boilerplate template and can see the same "cannot find module" error in the logs.
Code: https://vercel.com/templates/react-router/react-router-boilerplate
Deployed: https://test-rr-one.vercel.app/


Minimarcel (@minimarcel) · 2025-10-29

Hi team,

Thanks for reporting this error @gregoryzeng!
We experience the same issue, yesterday the very same builds were working perfectly and today we have this error as well!


Amy Egan (@amyegan) · 2025-10-29

Thanks for reporting this. We’re investigating similar reports now


Team Simulation (@team-9091) · 2025-10-29

We are having the same exact issue.
Is there any updates?


Amy Egan (@amyegan) · 2025-10-29

@gregoryzeng @minimarcel @team-9091 We just shipped a fix. Can you redeploy and let me know whether or not it works for you now?


Minimarcel (@minimarcel) · 2025-10-29 · ♥ 1

It works for us! Thanks!


Gregoryzeng (@gregoryzeng) · 2025-10-29 · ♥ 1

It's working now. Thanks for the quick support!


Thornhill (@thornhill) · 2025-11-03

hey guys! I’m still getting this issue when deploying using the vercel cli, just updated using npm i -g vercel@latest but still getting the same issue where the build and deployment succeeds but any request results in a 500 with: Cannot find module '/var/task/node_modules/@mjackson/node-fetch-server/dist/node-fetch-server.cjs'