Sharing to facebook

I am once again stuck and need some help!
I have taken a recording of some footage on my NVR using my phone and Hikconnect app. I need to share this on facebook to a comunity group but it will not allow me to select the videos. Anything else will select just nothing from hikconnect.

Is this a recording problem or facebook? It says they are .mp4 format so i just presumed it would upload.

Thanks yall