I just signed up and received a key from the Census API. I created a query, copied the key into the query and submitted it.
The response said:
A valid key must be included with each data API request. You included a key with this request, however, it is not valid. Please check your key and try again.
If you do not have a key you my sign up for one here.
I am not sure how I could have screwed this up here... Any suggestions ?