Here are a few steps you need to follow to be able to run reports from CCAWebAPI . . .

1/ Get the list of reports and Ids:

GET: http://[WebServer]/CcaWebAPI/Reports

Extract:
{
 "CcaObjectTypesUsedInParameters": [
 7
 ],
 "Revision": 0,
 "Type": 0,
 "CcaObjectType": 30,
 "DateCreated": "2018-02-23T10:07:55.999",
 "DateModified": "2018-02-23T10:07:55.999",
 "Description": "Standard Report (v2)",
 "Id": 2,
 "Name": "Agent Outbound Calls (v2)"
 },

2/ Get a list of the parameters for a specific report (here the "Agent Outbound calls (v2)" with ID=2):

{
 "Request": {
 "Method": "GET",
 "Url": "http://[WebServer]/CcaWebAPI/Reports/2/parameters"
 },
 "Version": "5.4.9.6",
 "StatusCode": 200,
 "Response": [
 {
 "AllowBlank": false,
 "DataType": 31,
 "DefaultValues": null,
 "Hidden": false,
 "MultiValue": true,
 "Name": "Filter1",
 "Nullable": false,
 "Prompt": "Task?"
 },
 {
 "AllowBlank": false,
 "DataType": 4,
 "DefaultValues": null,
 "Hidden": false,
 "MultiValue": false,
 "Name": "Filter3",
 "Nullable": false,
 "Prompt": "Time interval?"
 }
 ]
}

3/ Run the report: E.g. outbound calls on survey id 1371 from 03 SEP 2019 00h00 until 17 SEP 2019 23h59 and get the result in a PDF file.

POST: http://[WebServer]/CcaWebAPI/Reports/2/Run?output=1

Header:

Add the Content-Type = application/json . . .

Body:

{
 "Filter1": "1361","Filter3": "2019-09-03T00:00:00;2019-09-17T23:59:59"
}

Output: 

You will get an answer from the API with a QID:

{

 "Request": {

 "Method": "POST",

 "Url": "http://[WebServer]/CcaWebAPI/Reports/2/Run?output=1"

 },

 "Version": "5.4.9.6",

 "StatusCode": 200,

 "Response": {

 "qid": 193

 }

}

 4/ Then download your file with the QID received:

http://[webserver]/CcaWebAPI/Reports/Requests/193/download