What Happens When Consumption Fails?
If the API consumption encounters a problem due to one or more of the following reasons, a 500 SOAP fault is returned:

If the API key value in the HTTP header or the query string is authenticated as invalid.
The sample message looks like this:
The request is authenticated as invalid.

If the HTTP header is not present in the request.
The sample message looks like this:
A required header is missing in the request.

If the API key value in the HTTP header is expired.
The sample message looks like this:
The API key has expired.