I've searched this forum and every MMS thread i've read pertained to Rogers.
Everytime I try to send an MMS picture message, I get a red x and the error "Failed to send message." I have 2 MMS service books and under TCP settings I have the cingulargprs apn. Ive reregistered numerous times under Host Routing Table. If i click on show details on the mms message, I get this error:

"Error 403: you are not authorized to view this page. Please try loading a different page."

I was able to send MMS messages on my Curve before I switched to the Bold.

Any help would be greatly appreciated!