Can I export the mp4 video file to my phone from Video Security App?
According to the release note of the Video Security Client (page 3), you will notice that it is specified that the export of the mp4 video using the Video Security App on iOS or Android device is not possible, while for PC should work without issues.
Therefore, if you still want the mp4 video, you can use the VSC for PC:
Nice to know:
As additional guides, please refer to the following KB articles: