It's unclear what you are hoping to get in the response payload.
Calling on /attask/api/v14.0/PTLSEC? will return a list of reports, not the actual data that those reports display when viewed in a browser.
If you have a report that you view in browser and you're wanting to fetch the same data that's displayed in that report via API, you need to reconstruct the logic of the report into your query parameters, and call on the object type being reported.
E.g., if you have a project report that displays all active projects owned by John Doe, with columns for status and planned completion date, and you want to get those same results via API, then you need to build that same logic into your query:
https://domain.my.workfront.com/attask/api/v15.0/PROJ/search?ownerID=John's_ID&status=CUR&fields=status,plannedCompletionDate
Suggest reading this article for more examples:
https://experienceleague.adobe.com/docs/workfront/using/adobe-workfront-api/api-general-information/...
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