Error map
Dynamic server usage Error: Dynamic server usage: Route /x couldn't be rendered statically because it used `cookies`
React · 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)
Warning: Functions are not valid as a React child. This may happen if you return a Component instead of <Component /> from render.
A function (usually a component itself) was rendered instead of calling/rendering it as an element.
Error: Functions cannot be passed directly to Client Components unless you explicitly expose it by marking it with "use server".
A Server Component passed a function prop to a Client Component.
Error: Hydration failed because the initial UI does not match what was rendered on the server
The HTML rendered on the server differs from the first client render, so React (Next.js/Remix) can’t attach to it.
Error: Invalid src prop on `next/image`, hostname "x" is not configured under images in your `next.config.js`
next/image refuses to optimize images from domains not allowed in next.config.js.
Error: async/await is not yet supported in Client Components, only Server Components.
A component marked "use client" was declared async.
Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined
JSX referenced a component that is undefined — almost always a default/named import mismatch.
Error occurred prerendering page "/x". Read more: https://nextjs.org/docs/messages/prerender-error
A page threw an error while Next.js was rendering it at build time.
Warning: Each child in a list should have a unique "key" prop
When rendering a list with `.map()`, each element needs a stable, unique `key` so React can track items between renders.
Warning: Cannot update a component (`Parent`) while rendering a different component (`Child`)
A child component updated a parent’s state during its render instead of in an effect or event handler.
Error: A component suspended while responding to synchronous input.
A component suspended (lazy load or data fetch) during an update that wasn’t wrapped in a transition, and there is no Suspense bo…
Next.js: Error: NEXT_REDIRECT (redirect() inside try/catch)
redirect() works by throwing a special error; catching it in try/catch (or a .catch) swallows the redirect and logs NEXT_REDIRECT.
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.
Two steps away (25)
Error: Objects are not valid as a React child
You tried to render a plain object (or a Promise/Date) directly in JSX; React can only render strings, numbers, elements and arra…
Error: Too many re-renders. React limits the number of renders to prevent an infinite loop.
A state update runs during render, which triggers another render, which updates state again — forever.
Error: Nothing was returned from render. This usually means a return statement is missing.
A component returned undefined (React 17 and earlier) — usually a missing return or a return followed by a line break.
You're importing a component that needs useState. It only works in a Client Component but none of its parents are marked with "use client"
In the Next.js App Router, a component using hooks or browser APIs is rendered as a Server Component.
Error: NextRouter was not mounted.
next/router’s useRouter was used inside the App Router (app/ directory), which uses next/navigation instead.
Next.js: You're importing a component that needs "server-only". That only works in a Server Component
A Client Component (or a file it imports) pulls in server-only code — database clients, secrets, next/headers or a module marked…
ReferenceError: x is not defined
Code refers to a variable or function name that doesn’t exist in the current scope.
Error: Invalid hook call. Hooks can only be called inside of the body of a function component.
A hook ran outside a function component/custom hook, conditionally — or two copies of React are loaded.
Warning: validateDOMNesting(...): <div> cannot appear as a descendant of <p>.
The JSX produces invalid HTML nesting, which also causes hydration mismatches in SSR.
Kubernetes: ImagePullBackOff / ErrImagePull
The node can’t pull the container image — wrong name/tag, missing registry credentials, or registry unreachable.
exec /usr/local/bin/docker-entrypoint.sh: exec format error
The container tried to run a binary built for a different CPU architecture (arm64 vs amd64) — or a script with a broken shebang /…
conflict: unable to remove repository reference (must force) - container is using its referenced image
You tried to delete an image that a container — even a stopped one — still uses.
TypeError: x is not a constructor
new was used with something that isn’t a class/constructor — usually a wrong import.
Go: declared and not used: x / "fmt" imported and not used
Go refuses to compile code with unused local variables or unused imports.
'react-scripts' is not recognized as an internal or external command / react-scripts: command not found
node_modules is missing or broken, so the react-scripts binary isn’t available.
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…
Dockerfile parse error line N: unknown instruction
A line in the Dockerfile doesn’t start with a valid instruction — usually a broken line continuation or a typo.
IndexError: list index out of range
Code accessed a list position that doesn’t exist.
Warning: `key` is not a prop. Trying to access it will result in `undefined` being returned.
A component tried to read props.key, which React reserves and never passes down.
Warning: A component is changing an uncontrolled input to be controlled
An input’s `value` started as `undefined` (uncontrolled) and later became a defined value (controlled), or vice versa.
java.lang.IllegalStateException
A method was called when the object wasn’t in the right state for it.
TypeError: Cannot assign to read only property 'x' of object
Code tried to modify a frozen object, a getter-only property, or immutable state.
Next.js 15: Route "/x" used `cookies().get('token')`. `cookies()` should be awaited before using its value
Since Next.js 15, cookies(), headers(), params and searchParams are async — they must be awaited.
Error: Cannot find module 'x' (MODULE_NOT_FOUND)
Node can’t resolve the module path — the package isn’t installed, or a relative path/extension is wrong.
ChunkLoadError: Loading chunk 123 failed.
A lazily loaded JavaScript chunk couldn’t be downloaded — usually because a new deployment removed the old hashed files.
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