If an error occured during the processing of the cross-match job, the service will return one of the following HTTP codes:
a code 400 if there was an error in the input parameters (missing parameter, unknown table name, etc), or if something went wrong during the processing of the job.
a code 503 if the service is overloaded. In this case, try to resubmit your job later.
In addition, a VOTable document is returned, including the following snippet: <INFO name="QUERY_STATUS" value="ERROR">...</INFO>. The text value of this INFO element provides with an explicit explanation of the origin of the problem.
Example:
<?xml version="1.0" encoding="UTF-8"?>
<VOTABLE ... >
...
<RESOURCE type="results">
<INFO name="QUERY_STATUS" value="ERROR">
Message: Missing parameter RESPONSEFORMAT.
...
</INFO>
</RESOURCE>
</VOTABLE>