@HiroakiS6393

I think because of content type is multipart/form-data so you can't inbound content to Text property. When response is multipart/form-data, pega default set it into pyResponseAttachmentPage pega

Please test download file by add the java method below after using connect rest in activity or add activity in Post load processing in case use Data Page connect rest

final ClipboardPage attachPage = tools.findPage("pyResponseAttachmentPage");

if (attachPage != null){
  
  fileName = attachPage.getProperty("pyAttachNames(1)").toString();
  ClipboardProperty attachVals = attachPage.getProperty("pyAttachValues(1)");
  byte[] byteArray=Base64Util.decodeToByteArray(attachVals.toString());
  try{
      String sErrorMessage = tools.sendFile( byteArray, fileName, false, null, true ); 
}catch (Exception e) {
 oLog.error("Error file: " + e.getMessage());
}
}