It was a configuration issue indeed. Unfortunately to the other side. I am afraid we don't do street level geocoding and both xml and json should have returned an empty result set for this query.
Is this a dropped feature? I didn't see any blog or forum posts regarding rolling back. Previously, street-level geocoding seemed to work for at least the US and the UK.
Do you have any alternatives to online TIGER geocoding webservices which also use a CC license?
It is not a dropped feature since it was never officially supported in the API. It should only be supported on the website to move to the correct place when adding new locations.