@Matt_hew_ asked @VZWSupport on twitter:
Q: Why won’t MMS (multi-media messaging service) messages work over Wi-Fi?
A: Multi-media messaging service messages will not work over Wi-Fi. They require the data network send and receive. Ensure your mobile data connection is enabled to use MMS.
The only way MMS messages can be sent and received over Wi-Fi is if the phone sending or receiving the MMS message is Wi-Fi Calling capable and has Wi-Fi Calling turned on and activated.
Well, maybe my MMS messages on my Droid Turbo 2 are not going over my WiFi as I have a 3G Network Extender providing a signal in my apartment. I don't have WiFi calling enabled. My iPad, however, is data only and has Cellular Data turned OFF. It is ONLY connected via my WiFi and it handles MMS messages fine.