Scenarios: Use siri to send text message to someone with an iphone and imessage enabled, success! (blue messages) Use siri to send text message to anyone with SMS phone, fail, undeliverable. (green message). If I click on the message and say try again, it does deliver. But it will always fail the first time. This includes originating new messages and replying to existing ones. This is brand new behavior that didn't used to happen. I checked the only obvious thing I could think of, that phone numbers were somehow now iphone instead of mobile. No luck. As I said, this didn't used to be an issue. I'd get the occasional failed delivery of a message but that was due to network errors and actually timing out, not a stupid in the phone itself. At least I think this is a phone stupid. Iphone 4S, latest IOS, Sprint.