SvelteKitError: Not found: /undefined/get-paginated in Docker Container

I am encountering an issue with loading environment variable in my SvelteKit application when running it inside a Docker container. This question is extended from this question

The error I'm seeing is:

SvelteKitError: Not found: /undefined/get-paginated    at resolve2 (file:///app/build/server/index.js:3850:18)    at resolve (file:///app/build/server/index.js:3682:34)    at Object.handle (file:///app/build/server/chunks/hooks.server-JRK4nkXw.js:31:26)    at respond (file:///app/build/server/index.js:3680:43)    at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {  status: 404,  text: 'Not Found'}

Dockerfile:

FROM node AS builderWORKDIR /appCOPY package*.json .RUN npm ciCOPY . .RUN npm run buildRUN npm prune --productionFROM nodeWORKDIR /appCOPY --from=builder /app/build build/COPY --from=builder /app/node_modules node_modules/COPY package.json .EXPOSE 3000ENV NODE_ENV=productionCMD ["node", "build"]

Docker run command:

docker build -t my-frontend .  //build successfully.docker run -p 3000:3000 \  -e PUBLIC_BACKEND_SERVER_URL=http://localhost:4000 \ my-frontend

When I build and run the application without Docker, it works as expected. The build process is following the SvelteKit documentation on environment variables.

import { get, type Writable } from "svelte/store";import { collectionObj } from "./store";import { PUBLIC_BACKEND_SERVER_URL } from "$env/static/public";// Define the options for the fetch requestconst options = {    method: "POST",    headers: { "Content-Type": "application/json" },    body: JSON.stringify({...}),};// Fetch function to get paginated postsexport const fetchPaginatedPosts = async (key: string = "posts", last_id: string = "") => {  collectionObj.set(key);  console.log("de: ", get(collectionObj));  try {    const response = await fetch(      `${PUBLIC_BACKEND_SERVER_URL}/get-paginated`,      options    );    if (!response.ok) {      throw new Error("Network response was not ok");    }    const res = await response.json();    console.log("API call");    return res;  } catch (error) {    console.error(error);    throw error;  }};

svelte.config.js:

import adapter from '@sveltejs/adapter-node';import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';/** @type {import('@sveltejs/kit').Config} */const config = {  preprocess: vitePreprocess(),  kit: {    adapter: adapter({ out: 'build', precompress: false, envPrefix: '', polyfill: true })  }};export default config;

What could be causing the /undefined/get-paginated error in the Docker container, and how can I resolve it?