There may be a blocking issue in regards to your texting to short codes. I gather you are not having issues with sending text messages to any regular numbers? I will send you a private message so I can gather some additional information.
I also have never been able to shortcode text on my evo4g. I called Sprint about a possible block and they seemed unable to help me. I would love to be able to shortcode text. Can you help me, too?
I am also not able to send shortcode messages from my Evo 4G, never have been and sprint has been unable to help.
Please send me a private message and once I get your message, I will reply back to get more information from you.
Could you please send me a private message with the exact error message and your phone number and pin code or security question answer so I can access the account.