The reason why the mobile phone gallery can't send the original video shows that it has been sent is that the video is too big, which leads to problems when uploading. You can try to solve the problem by the following steps:

1. Modify the video name and video format to reduce the video size.

2. Use cloud disk or external storage, such as USB flash drive and mobile hard disk, to upload the video to the cloud or external storage.

3. Share the video to the receiver by using the sharing function of cloud disk or external storage.

4. If the above methods can't solve the problem, you can try to upload the video by other methods, such as uploading the video by using a third-party application.