Why does media object List REST call return no content?

I'm trying to get a list of media object attachments using AIS REST call.  I'm able to upload a new file so I know there is content, but the list command returns 204 no content. I don't know how to debug this issue.

Here's the JSON I'm using:

{

"token": "044RoMMUfKeZPawk/jShHrDbt+E+7hYNVINluGC/kU0Smw=MDE5MDEyMTU5MTA0ODIxNzUwMzQxOTc1M0F6dXJlY2xpZW50MjE1MDg4NTczOTQ2NzU=",

"moStructure": "ABGT",

"moKey": ["17094"],

  "formName": "P01012_W01012B",

"version": "ZJDE0001",

"includeURLs": true,

  "includeData": true,

  "moTypes": [

        "FILE",

        "QUEUE",

        "TEXT",

        "URL"

    ],

    "thumbnailSize": 0

}