Error map
404 on page refresh (history mode) Browser: Cannot GET /users/42 — refreshing a Vue Router history-mode page returns 404
Vue · layer 1, On your device
Centre: this error. First ring: errors it is linked with (12). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (12)
Failed to load module script: Expected a JavaScript module script but the server responded with a MIME type of "text/html"
A or dynamic import got HTML back instead of JavaScript.
Refused to execute script from 'x' because its MIME type ('text/html') is not executable
The browser fetched a script but the server labelled it text/html (usually an error page), so it refused to run it.
SyntaxError: Unexpected token '<' (HTML served instead of JavaScript)
The browser loaded a .js file but received HTML (an error page or the SPA index.html).
ChunkLoadError: Loading chunk 123 failed.
A lazily loaded JavaScript chunk couldn’t be downloaded — usually because a new deployment removed the old hashed files.
Firebase Hosting: Page Not Found — This file does not exist and there was no 404.html or index.html found in the document root
A single-page app route returns 404 when opened directly or refreshed, because Firebase Hosting looks for a real file at that pat…
Vue: TypeError: Failed to fetch dynamically imported module: https://app.example.com/assets/Settings-abc123.js
A lazy-loaded route/component chunk couldn't be loaded (new deployment removed old chunks, network issue, or wrong base path).
Vue Router: Uncaught (in promise) NavigationDuplicated: Avoided redundant navigation to current location: "/home"
`router.push` to the route you're already on, rejecting the promise (Vue Router 3.1+).
Vue Router: [Vue Router warn]: The "next" callback was called more than once in one navigation guard when going from "/a" to "/b"
A navigation guard called `next()` more than once, which breaks navigation.
Next.js: Error: Failed to find Server Action "abc123". This request might be from an older or newer deployment
The browser called a Server Action ID the current server build doesn't know — usually a version skew after a deploy.
Next.js: Error: Could not find a production build in the '.next' directory. Try building your app with 'next build' before starting the production server
`next start` was run without a prior successful `next build` (or the `.next` folder is missing).
Vue Router: [Vue Router warn]: No match found for location with path "/users/42"
The router has no route record matching that path (typo, missing route, or case/base issue).
Vue Router: [Vue warn]: injection "Symbol(router)" not found. / Cannot read properties of undefined (reading 'push')
`useRouter()`/`useRoute()` ran in a component tree where the router plugin isn't installed.
Two steps away (32)
Azure App Service: ":( Application Error" / container didn’t respond to HTTP pings
App Service started your app but it crashed or never listened on the expected port.
Could not load file or assembly 'X, Version=…' or one of its dependencies
The runtime couldn’t find or load a referenced DLL — missing from the output, wrong version, or wrong platform (x86/x64).
PHP still runs old code after deploy (OPcache not reset)
OPcache keeps serving cached bytecode, so changes uploaded to the server don’t take effect.
The framework 'Microsoft.NETCore.App', version '8.0.0' (x64) was not found. You must install or update .NET to run this application
The machine doesn’t have the .NET runtime version the app was built for (framework-dependent deployment).
Console: Refused to apply style from 'https://…/style.css' because its MIME type ('text/html') is not a supported stylesheet MIME type
The stylesheet URL returned something that is not CSS — usually a 404/HTML error page — and `X-Content-Type-Options: nosniff` mak…
Console: Failed to register a ServiceWorker: A bad HTTP response code (404) was received when fetching the script
The browser could not fetch, parse or install the service worker script, or the page is not allowed to register one (HTTPS and sc…
SyntaxError: Unexpected token < in JSON at position 0
`JSON.parse()` / `response.json()` received something that isn’t JSON — very often an HTML error page.
SyntaxError: missing ) after argument list
A function call’s parentheses are unbalanced — often an unescaped quote or a missing comma/plus.
SyntaxError: Identifier 'x' has already been declared
The same let/const/class name was declared twice in the same scope.
DOMException: Failed to execute 'querySelector' on 'Document': 'x' is not a valid selector
The CSS selector string is invalid — often an ID starting with a digit or containing special characters.
Module not found: Can't resolve 'fs' (Next.js / webpack 5)
A Node.js built-in (fs, path, crypto, net) is imported into code that runs in the browser bundle.
Module parse failed: Unexpected token. You may need an appropriate loader to handle this file type
Webpack found syntax it can’t parse because no loader is configured for that file (JSX, TypeScript, CSS, or modern syntax in node…
Error: Minified React error #31; visit https://react.dev/errors/31 for the full message
A production React build threw an error whose message was shortened to a number.
Firebase CLI: Error: Authentication Error: Your credentials are no longer valid. Please run firebase login --reauth
The Firebase CLI's saved login expired or was revoked.
Firebase CLI: Error: Your project my-app must be on the Blaze (pay-as-you-go) plan to complete this command. Required API cloudbuild.googleapis.com can't be enabled until the upgrade is complete
Deploying Cloud Functions needs the Blaze plan because it relies on Cloud Build and Artifact Registry.
[vite] Internal server error: Failed to resolve import "x" from "src/App.jsx". Does the file exist?
Vite couldn’t find an imported file or package.
Vue: [plugin:vite:vue] Duplicate attribute. / [vue/no-duplicate-attributes] Duplicate attribute 'class'
The same attribute appears twice on an element in a template.
Vite/Vue: [plugin:vite:import-analysis] Failed to parse source for import analysis — you may need to install appropriate plugins to handle the .vue file format
Vite can't process `.vue` files because the Vue plugin isn't installed/enabled.
Vue: [Vue warn]: Failed to resolve component: x
The template uses a component tag that isn’t registered or imported where it’s used.
Vue: [Vue warn]: Avoid mutating a prop directly since the value will be overwritten whenever the parent component re-renders
A child component assigned to a prop. Props flow one way — the parent owns the value.
Next.js: You have a Server Component that imports next/router. Use next/navigation instead
`next/router` (Pages Router) was imported in an App Router component.
Pinia: Error: [🍍]: "getActivePinia()" was called but there was no active Pinia. Are you trying to use a store before calling "app.use(pinia)"?
A store was used before Pinia was installed or outside a component context (router guards, plain modules).
Next.js: FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory (during next build)
Node ran out of memory while building a large Next.js app (or on a small CI/Vercel runner).
Next.js: Error occurred prerendering page "/blog" TypeError: fetch failed { cause: Error: connect ECONNREFUSED 127.0.0.1:3000 }
During `next build` a page tried to fetch data from a server (often your own app or an API) that isn't running yet.
Next.js: Error: Server actions must be async functions
A function marked `"use server"` isn't declared `async`.
Next.js: Page "/blog/[slug]" is missing "generateStaticParams()" so it cannot be used with "output: export" config
A dynamic route can't be statically exported without telling Next.js which paths to generate.
Next.js: Module not found: Can't resolve '@/components/Button' / 'lodash' in '/app/src'
Webpack/Turbopack couldn't resolve an import — wrong path/alias, missing dependency or case mismatch.
Next.js: Failed to compile. ./src/app/page.tsx 12:7 Error: 'x' is assigned a value but never used. @typescript-eslint/no-unused-vars
`next build` runs ESLint and fails the build on lint errors.
TypeError: Missing parameter name at 1 (path-to-regexp)
An Express 5 (path-to-regexp v8) route uses old wildcard syntax like '*' or '/:id?'.
No routes matched location "/x"
React Router found no route definition for the current URL.
Error: NextRouter was not mounted.
next/router’s useRouter was used inside the App Router (app/ directory), which uses next/navigation instead.
Vue: [Vue warn]: injection "theme" not found.
`inject("theme")` ran but no ancestor provided it.
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Popular: 500403400ORA-009331064Critical errorFileNotFoundException assemblyTypeError