Attaching a video to an email with xfinity app.

How can I attach a video to an email using the xfinity app? The only thing I can attach to an email is a photo using the app. When I select attachment in my email, it says photo or camera and I select photo and it goes to where my photos and videos are stored but I can only select photos. The video icons are there but I can select them. They are faded out. I can send videos using my computer using windows but not on my iPhone using the app.