[Solved] POST REFUND returned error 400 since Feb ~10th [closed]

Question

Since you’re using Google App Script, it looks like you have to set the Content-Type header using the special contentType parameter (docs here). That way, Google Apps Script knows to serialize the payload as JSON rather than multipart form data. If you just specify it as a header, Google will override it.

Accepted Answer

Since you’re using Google App Script, it looks like you have to set the Content-Type header using the special contentType parameter (docs here). That way, Google Apps Script knows to serialize the payload as JSON rather than multipart form data. If you just specify it as a header, Google will override it.