The truth is I’m not a regular user of the receiving and sending MMS but one. These days I received a Vodafone MMS advertising but the download gave me an error message “Generic error in the network. ” I found the Vodafone MMS APN was correct, wanted to check that web via the MMS service was active, but gave an error so I called the SAT Vodafone and they confirmed that it was all right.
After trying several times, I thought the wifi disconnect (when I’m at home whenever I connect via wifi) and try to download the message. At that time having GPRS data connection is successfully downloaded. As strange to me, I turned to connect to the wifi and I sent a MMS from another terminal and again the same problem, with the active wifi gave the error when downloading and when I connect via GPRS is working fine.
I do not know if android is a failure or HTC Desire Z, searching the internet find this bug with different terminals. At least in my case was settled disconnecting from wifi to download.