Anyone receiving MMS from non-iPhones? If so, from non-iPhones on a different carrier than yours? I am able to send and receive MMS to/from other iPhones but when someone without an iPhone sends me an MMS, I receive: "Callback #: XXX-XXX-XXXX". This was not an issue with iPhone OS 3.x. I've reproduced the problem on three different phones all running iOS 4 (a 3GS and 2x iPhone 4's). On all three iPhones, we have tried resetting network settings, but this doesn't fix it.