> For the complete documentation index, see [llms.txt](https://docs.aurelia.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aurelia.io/developer-guides/error-messages/0001-to-0023/aur0008.md).

# AUR0008

Unable to resolve key: yyyy

### **Error message**

Unable to resolve key: `yyyy`

### **Parameters**

key (string)

### Error explanation

This error occurs when the DI container is unable to resolve the specified key using any of its registered strategies. This typically means that the key was never registered, was registered incorrectly, or there is a typo or mismatch in the key being requested.

### Common causes

* The key was never registered with the container.
* There is a typo or mismatch in the key used for registration and resolution.
* The registration was accidentally removed or not included in the current container scope.
* A plugin or library expected to register the key did not do so.

### How to fix

* Ensure the key is registered with the container before attempting to resolve it.
* Double-check that the key used for registration matches the key used for resolution.
* If using plugins or libraries, ensure they are properly configured and registered.

### Debugging tips

* Check the stack trace to see where the resolution was attempted.
* Search your codebase for all registrations and resolutions of the key in question.
* If using plugins, try disabling them one at a time to isolate the source.


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