# AUR3400

## Error Message

`AUR3400: Invalid component %s: must be either a class, a custom element ViewModel, or a (partial) custom element definition`

## Description

This error occurs when the router is asked to navigate to (or generate instructions from) a “component” value that is not a supported component type.

## Common Scenarios

* Passing a promise, plain object, or other non-component value as a route component.
* Using an import incorrectly (for example passing the module object instead of the exported class/definition).

## Solutions

* Ensure the value passed as a component is one of:
  * A custom element class (view-model)
  * A custom element view-model instance (where supported)
  * A custom element definition/partial definition

## Troubleshooting

* Log the `%s` value to see what was passed.
* Ensure you’re importing the correct export from your module.