If you see this text in a WhatsApp chat or a backup folder but the video won't play, it means the file is no longer on your phone's internal storage.
If you have auto-backup enabled, the video may be stored in the cloud under the date October 9, 2019 . Download VID 20191009 WA0000 mp4
Are you trying to a deleted video, or did you find this link in a specific tutorial you're following? If you see this text in a WhatsApp
Search for a "WhatsApp Video" folder.