Most of the time, there's a small typo in the recipient's email address. Please double-check it.
If the address is correct, the email may be in the recipient's spam or junk folder. Ask them to add PNP to their safe senders: see How do I make sure I receive email notifications from PNP?
You can also share the video another way: open it in My Creations, click Share and use Share link to copy the link and send it yourself.