I have a BBZ10 on Verizon and until today, I have been able to send MMS to anyone on any network and today I tried to send an MMS to an iPhone on AT&T and got an red error msg :"Invalid Desitination Address." I sent an MMS to other cell phones locally on Verizon without fail and was able to send several SMS msgs to the AT&T iPhone without fail. I can not find any troubleshooting steps to take. Any body got a suggestion? Hope there is hope..