# AUR3167

## Error Message

`AUR3167: The provided container has no registered IAppRoot. RouteContext.setRoot can only be used after Aurelia.app was called, on a container that is within that app's component tree.`

## Description

This error occurs when the router expects an Aurelia `IAppRoot` to be registered in the container tree, but none is found. This typically means the router is being used before the Aurelia app is configured/started, or from a container outside the app’s DI tree.

## Solutions

* Ensure you call `Aurelia.app(...)` before using router APIs that require a root context.
* Ensure you use the router from the same container tree as the running Aurelia app.

## Troubleshooting

* Verify router configuration is registered in the same container as the app (or a descendant).
* Ensure you are not constructing a router with a different container than the app uses.


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