I am consistently having a problem sending anything other than a text message with emojis to one specific contact who has an iPhone. I can send images, contact cards, GIFs, etc. to all other contacts with iPhones.

When I try and send this contact a picture/contact card/etc. I get the message "Error: Message not sent invalid address." I've tried reformating their number, deleteing an re-entering thier contact, clearing my cache. It's just this one contact. Does anyone have any suggestions?