I saw a problem yesterday with a WebServices REST (v3.3) job. The job was ending with the status FAULT_POST_PROCESSING, and these error messages:
U00021719 Syntax error in object 'UC4.SCM.V140.DEPLOY.OI.DEPLOY.JOBS_REST', line '00000'.
U01001307 A variable name with the length 0 is not allowed.
Obviously, line 00000 makes no sense, and commenting out the entire post process did not resolve the problem. After some more tinkering, I discovered that the problem lay not with the Post Process tab of the job, but with the Response section of the Web Service tab. Under the Response section, in the Headers tab, I had defined a single entry to take the content of one response header and store it in a variable. It initially looked okay, but eventually I discovered that the variable name needed to be specified without the leading ampersand (&) character.
It would obviously be preferable if the Automation Engine returned a more informative message in such situations.
It would also be nice if the WebServices REST documentation mentioned that the leading ampersand should be omitted.
We actually just had a similar issue a few days ago. In this case it was a cert issue with the endpoint.
To add to this even if there is no response back from the endpoint it will still fail with the same error.
Report of the REST Job:
Not really sure how to get a better error message as the report parsing I do would be in the post process.
I presume that this combination of circumstances means that there is a problem in the response handling section of the WebServices job: