I've been having issues with my group messages & MMS for years over various phones and various carriers with messages like "Message expired or not available" & "Messages waiting to be downloaded. I lose too much info that I need for work and my personal life. After some internet sleuthing, I realized that my APN is listed, but the following fields are listed as "not set": MMSC, MMS Port. I'm hoping that these can help eliminate any more years of misery. I've always set up my phones at home, and never at a store which might be why it's never been set up correctly.
Please help!