Same issue here with S10. Spent hours talking to Xfinity in chats, days at Xfinity store. Odd thing is that MMS (sending photos) worked perfectly in their store, on their wifi. It just doesn't download or send MMS at my house. Oddly it works fine on work on wifi, I even received a text picture the other day in Safeway (on their wifi). All the resets have been done, all the settings toggled on, off. I tried another persons idea, turning on airplane mode...sending a picture...it showed pending...when I clicked off airplane mode it sent it over my home wifi. Now it is back to not working. Any final solutions to this MMS problem? Thanks for your time.