Resource key "yyyy" already registered
Invalid resolver strategy specified: yyyy
resource key
This means there is a resource with that name already registered with a container
Consider using a different name for the resource (element/attribute/value converter/binding behavior etc...).
Please also note that this error could be caused by a plugin and not your application. After ruling out that the error is not being caused by your code, try removing any registered plugins one at a time to see if the error resolves itself.