# AUR0017

### **Error message**

Failed to instantiate 'xxxx' via @newInstanceOf/@newInstanceForScope, there's no registration and no default implementation, or the default implementation does not result in factory for constructing the instances.

### **Parameters**

Interface key (string)

### Error explanation

This error occurs when you attempt to instantiate an interface using `@newInstanceOf` or `@newInstanceForScope`, but there is no registration for the interface, no default implementation, or the default implementation does not provide a factory for constructing instances. The DI system cannot create a new instance without a valid registration or factory.

### Common causes

* The interface was not registered with a concrete implementation.
* The default implementation for the interface does not provide a factory.
* There is a typo or mismatch in the interface key used for registration and resolution.
* A plugin or library expected to register the interface did not do so.

### How to fix

* Register the interface with a concrete implementation using the DI container.
* Ensure the default implementation provides a factory for constructing instances.
* Double-check that the interface 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 instantiation was attempted.
* Search your codebase for all registrations and resolutions of the interface key in question.
* If using plugins, try disabling them one at a time to isolate the source.