Thank you!! I'm a new Sprint customer - switched to sprint about a month ago. Have never been able to send or receive MMS over wifi. Have tried multiple messaging clients (8 of them), and multiple wifi networks (home and work). My husband has the same phone and has the same problem.
Yes, wifi calling is turned on. I have tried to send and receive with wifi calling on + data turned on; also tried to send/receive with wifi calling on + data turned off. None of these enable me to send/receive MMS.