You need to clarify------on the phone, are you using the Mail app that came on it? Or the Xfinity Connect app? Or only Safari and the webmail? Comcast email size is restricted to a total of 25 Mb including any attachments, and videos can eat that up real fast. You would be normally better served to host the video someplace like iCloud, Photobucket, Googe Drive or something similar, then just send your recipient a link.