getting <InternalFailure/>

[nikhilsquareboat]

I am trying to access AWS rekognition service

var instanceXML = AWS.request('rekognition', 'us-east-1','RekognitionService.ListCollections',null, "POST");

getting <InternalFailure/>

when I am hitting with post man I am getting proper data which is show below { "CollectionIds": [ "collection1", "collection2" ], "FaceModelVersions": [ "4.0", "4.0" ] }