Error map
NG8002 Angular: NG8002: Can't bind to 'ngModel' since it isn't a known property of 'input'
Angular · 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)
Angular: NullInjectorError: No provider for X!
Angular’s dependency injection couldn’t find a provider for a service/token the component needs.
Contact Form 7: There was an error trying to send your message. Please try again later.
The form submitted, but wp_mail() failed to send — the server can’t send mail or the mail settings are wrong.
ERR_CACHE_MISS: Confirm Form Resubmission
You pressed Back/Refresh on a page that was the result of a form POST, so the browser asks before sending the form again.
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.
django.template.exceptions.TemplateDoesNotExist: app/page.html
Django searched all template directories and couldn’t find that template.
Angular: NG0100: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked
A template value changed during the same change-detection cycle in which Angular already checked it (dev-mode only error).
Vue: [Vue warn]: Property "x" was accessed during render but is not defined on instance
The template references a variable/function that the component doesn’t expose.
Laravel: The GET method is not supported for route x. Supported methods: POST (MethodNotAllowedHttpException)
The URL exists, but not for the HTTP method used — e.g. opening a POST-only route in the browser, or a form sending GET.
Angular: NG8001: 'app-item' is not a known element — verify that it is included in the component's imports
The template uses a tag Angular does not recognise as a component — it was never imported (standalone) or declared/exported (NgMo…
Angular: NG8003: No directive found with exportAs 'ngForm' (template reference variable)
A template reference such as `#f="ngForm"` points at a directive Angular cannot find on that element — the module that provides i…
Angular: NG8004: No pipe found with name 'async' / 'date' / 'translate' — pipe not imported
The template uses a pipe Angular does not know — it is not imported into the component (standalone) or its module.
Angular: NG8113: NgIf is not used within the template of AppComponent — unused standalone import
A standalone component lists a directive, pipe or component in `imports` but never uses it in its template.
Two steps away (35)
InvalidOperationException: Unable to resolve service for type 'X' while attempting to activate 'Y'
ASP.NET Core’s dependency injection container can’t build Y because one of its constructor dependencies (X) was never registered.
UnsatisfiedDependencyException / NoSuchBeanDefinitionException: No qualifying bean of type 'X' available
Spring couldn’t find (or choose) a bean to inject.
The dependencies of some of the beans in the application context form a cycle
Two or more Spring beans depend on each other through constructors, and Spring Boot 2.6+ forbids cycles by default.
PHP mail() returns false / emails not delivered
PHP’s mail() function failed or emails never arrive (spam or rejected).
SES MessageRejected: Email address is not verified. The following identities failed the check in region
SES refused to send because the From address/domain isn’t verified — or the account is still in the SES sandbox, where recipients…
WordPress: 404 Not Found on every page except the homepage (permalinks / .htaccess / Nginx rules)
Pretty permalinks aren’t being routed to index.php — .htaccess is missing/ignored (Apache) or Nginx lacks try_files.
TypeError: Failed to fetch / NetworkError when attempting to fetch resource
The browser couldn’t complete the request at the network level — CORS, DNS, offline, blocked mixed content, or the server refused…
QuotaExceededError: Failed to execute 'setItem' on 'Storage': Setting the value exceeded the quota
localStorage/sessionStorage is full (about 5 MB per origin) or storage is disabled.
NotAllowedError: play() failed because the user didn't interact with the document first.
The browser blocked media autoplay with sound until the user interacts with the page.
TypeError: Cannot read properties of undefined (reading 'x')
You tried to access a property on a value that is `undefined` (or `null`) — usually data that hasn’t loaded yet or a wrong proper…
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.
TypeError: Cannot assign to read only property 'x' of object
Code tried to modify a frozen object, a getter-only property, or immutable state.
AttributeError: 'X' object has no attribute 'y'
You accessed an attribute or method that doesn’t exist on that object type.
ConnectionRefusedError: [Errno 111] Connection refused
Nothing is listening on the host/port Python tried to connect to.
django.db.utils.OperationalError: no such table: app_model
Django queried a table that hasn’t been created — migrations missing or not applied.
TS2564: Property 'x' has no initializer and is not definitely assigned in the constructor
With strictPropertyInitialization on, a class property declared without ? or a default isn’t set in the constructor.
Angular: Error: Cannot find control with name: 'email' (reactive forms)
A `formControlName` points at a control that does not exist in the bound `FormGroup`.
Angular SSR: NG0500: During hydration Angular expected <div> but found <span> (NG0501, NG0502)
The HTML rendered on the server does not match what the browser's Angular app tried to render, so hydration failed and the page w…
ReferenceError: x is not defined
Code refers to a variable or function name that doesn’t exist in the current scope.
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.
HTTP 404 Not Found
The server can’t find anything at the requested URL.
HTTP 405 Method Not Allowed
The URL exists, but it doesn’t accept the HTTP method you used (e.g. POST to a GET-only route).
Whitelabel Error Page — This application has no explicit mapping for /error
Spring Boot’s default error page — the request hit no controller mapping (404) or a controller threw (500).
Angular: NG8103: The *ngIf directive was used, but neither the NgIf directive nor the CommonModule was imported
A standalone component uses `*ngIf`, `*ngFor` or `ngClass` without importing the directive — or should migrate to the built-in `@…
Angular Material: Error: mat-form-field must contain a MatFormFieldControl
A `` has no Material input inside, or the module that provides `matInput`/`mat-select` is not imported.
Angular: NG0300: Multiple components match node with tagname app-x: A and B
Two components in scope share the same selector, so Angular cannot decide which one renders for that tag.
Angular: NG01203: No value accessor for form control with name: 'x' (ControlValueAccessor missing)
A form directive (`formControlName`, `ngModel`) is on an element or component that Angular cannot read/write values from.
Angular: NG01050: formControlName must be used with a parent formGroup directive
`formControlName` is used outside any `[formGroup]` — the control has no form to belong to.
Angular: NG01352: If ngModel is used within a form tag, either the name attribute must be set or the form control must be defined as 'standalone'
An `[(ngModel)]` input sits inside a `` but has no `name`, so Angular cannot register it as a form control.
Angular: NG0301: Export of name 'x' not found! (template variable #x="exportAs")
A template variable asks for a directive by `exportAs` name, but no directive with that export is on the element at runtime.
Angular: NG02100: InvalidPipeArgument: '[object Object]' for pipe 'AsyncPipe'
The `async` pipe received a plain object or array instead of an Observable or Promise.
Angular: NG02100: InvalidPipeArgument: 'Unable to convert "x" into a date' for pipe 'DatePipe'
The `date` pipe was given a value it cannot turn into a Date — an invalid string, a non-ISO format, `null` handled wrongly or a s…
Angular: NG02200: Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays
`*ngFor` (or `@for`) was given an object, `null` shape or a non-iterable instead of an array.
Angular: NG6008: Component X is standalone, and cannot be declared in an NgModule. Did you mean to import it instead?
A standalone component, directive or pipe was listed in an NgModule's `declarations` array.
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