SMS Message Results API POST task= results always sends back an empty array


With SMSsync we are trying to get the delivery reports of messages and per the documentation we are sending “message_uuids” through the GET task=result. It response to the API with something like this:
“message_uuids”: [

However, the POST task=results always sends back an empty array. Like this:
{“message_result”: [] }

Any help would be greatly appreciated. We have tried everything we can think of and are out of ideas on why the delivery report does not seem be working.