I am trying to submit the app review request. After I uploaded the video file in the app review request form, the file was not attached after the progress bar became 100%. I cannot submit the app review request, because the "Upload screencast showing the end-to-end user experience" was not marked as checked. I opened the developer console of the Chrome browser, it was the 400 Bad Request error. I'd like to know the limitation or something about uploading the screencast file, to avoid the error.

"Request for App Review" -> "Complete app verification" -> "Upload screencast showing the end-to-end user experience"