I had the same problem. I couldn't send nor recieve mms, and when i turned on my data connection everything was beginning send and i could recieve my old mms. Thanks for the help
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Ah, so your carrier has moved MMS out of the GSM signaling channel into the DATA channel, via their MMSC server (like most carriers).
People who routinely turn off their data, and then wonder why they can't send MMS are still under the assumption that MMS is handled the same as SMS. (It used to be that way back in the Pleistocene. But Smartphones forced carriers to move this all to the data channel because of large image size was chocking the Signaling Channel where SMS travels).
Some carriers set their MMS max size on their MMSC servers to prevent sending huge things (like entire songs and huge movies). As in phone Cameras deliver larger and larger photos they run up against these limits, if not on your carrier's end, then on the recipient's carrier's end.