# Node app Error on launch

**URL:** <https://community.fly.io/t/node-app-error-on-launch/21564>\
**Category:** JavaScript\
**Tags:** launcher, nodejs\
**Created:** [August 28, 2024, 9:11pm UTC](https://community.fly.io/t/node-app-error-on-launch/21564 "2024-08-28T21:11:37Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![leandrocunha](https://sea1.discourse-cdn.com/fly1/user_avatar/community.fly.io/leandrocunha/32/37590_2.png) [@leandrocunha](https://community.fly.io/u/leandrocunha)\
**Post date:** [August 28, 2024, 9:11pm UTC](https://community.fly.io/t/node-app-error-on-launch/21564/1 "2024-08-28T21:11:37Z")

</div>

I’m trying to launch a simlpe Node app but I got this error message:

“Error: failed to fetch an image or build from source: error building: failed to solve: failed to compute cache key: failed to calculate checksum of ref ###: “/app”: not found”

I don’t have a app folder on my app, how is pointed to there?

My dockerfile is below:

```auto
# syntax = docker/dockerfile:1

# Adjust NODE_VERSION as desired
ARG NODE_VERSION=21.7.3
FROM node:${NODE_VERSION}-slim as base

LABEL fly_launch_runtime="Node.js"

# Node.js app lives here
WORKDIR /dist

# Set production environment
ENV NODE_ENV="production"

# Throw-away build stage to reduce size of final image
FROM base as build

# Install packages needed to build node modules
RUN apt-get update -qq && \
    apt-get install --no-install-recommends -y build-essential node-gyp pkg-config python-is-python3

# Install node modules
COPY --link package-lock.json package.json ./
RUN npm ci

# Copy application code
COPY --link . .

# Final stage for app image
FROM base

# Copy built application
COPY --from=build /app /app

# Start the server by default, this can be overwritten at runtime
EXPOSE 3000
CMD ["npm", "run", "start"]

```

---

<div class="post-metadata">

**Author:** ![khuezy](https://avatars.discourse-cdn.com/v4/letter/k/4da419/32.png) [@khuezy](https://community.fly.io/u/khuezy)\
**Post date:** [August 28, 2024, 9:22pm UTC](https://community.fly.io/t/node-app-error-on-launch/21564/2 "2024-08-28T21:22:33Z")

</div>

> [@leandrocunha](#):
>
> `ARG NODE_VERSION=21.7.3`

You’re on an experimental release of `node` (odd number releases.) You should stick w/ the latest 20.x.x or `22.6.0` if you’re feeling lucky.

> [@leandrocunha](#):
>
> I don’t have a app folder on my app, how is pointed to there?

You’re trying to `COPY` from a non-existing folder:  
`COPY --from=build /app /app`

It looks like your Dockerfile is incomplete… I don’t see any build steps in it.

---

<div class="post-metadata">

**Author:** ![leandrocunha](https://sea1.discourse-cdn.com/fly1/user_avatar/community.fly.io/leandrocunha/32/37590_2.png) [@leandrocunha](https://community.fly.io/u/leandrocunha)\
**Post date:** [August 28, 2024, 9:43pm UTC](https://community.fly.io/t/node-app-error-on-launch/21564/3 "2024-08-28T21:43:56Z")

</div>

awesome, downgrade to **Node v20.12.2** and creating new files from a new `fly launch` solve the issue.

Thanks