When attempting to move a video file from the File tab of the Send menu to the Camera Roll, an error message appears: "The operation couldn't be completed (PHPhotosErrorDomain error 3302)." The cause of this failure is:
Contains an audio codec not supported by your iOS version
If the received video file is a file format supported by your iOS version but contains an audio codec that is not supported by iOS, it cannot be saved to Camera Roll of the native Photos app. For example, an MP4 video file supported by iOS contains a specific audio codec.
Not enough storage space on your iOS device
Since files are downloaded via Send Anywhere app, they are first saved in Files tab of Send Anywhere app's Send menu. Subsequently, they are moved to Camera Roll of the native Photos app. Video files that were initially saved in the Files tab of Send Anywhere app's Send menu are then deleted. Therefore, the process of moving files from the Files tab of Send Anywhere app's Send menu to Camera Roll of the native Photos app will temporarily consume storage space.
For example, if a video file is 30 GB in size, the process of saving it to Camera Roll of the native Photos app will temporarily require 30 GB of space in the Files tab of Send Anywhere app's Send menu and an additional 30 GB in the Camera Roll, resulting in a total of 60 GB. After the video is saved to Camera Roll of the native Photos app, it is removed from the Files tab of Send Anywhere app's Send menu. As a result, only 30 GB of storage space will ultimately be used on your device.