Unsupported content-type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

I have a request in JSON but the response has content-type as application/vnd.openxmlformats-officedocument.spreadsheetml.sheet . Basically, it downloads a file in xlsx but I am unable to find the file . It shows 'Unsupported content-type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' in the HTML tab even if we have content-disposition,content-type as headers in response.

I tried to save the response into a file through 'Create File' but it says invalid format. If i save the HTML tab manually , it gets saved in binary by default but if I change the extension to xlsx manually it works.

How to automate and get the file? Please help!