Hello, I'm having a mixed experience when sending SMS text messages. this has been going on for 3 or 4 months now. On the phone it appears that they have been sent. However, sometimes the recipients complain they haven't received them. My friend has the exact same model as me and is experiencing the exact same problem. His phone is on a different network, so it's not a network provider issue. A quick Google on the Internet reveals we are not alone in experiencing this issue. I have turned on the message delivery confirmation option, and I can see that when the issue occurs, the messages appear to be 'stuck' on the phone. They appear to not have been delivered to the network provider despite a full strength signal being shown by the phone. Sometimes I retry by composing an additional message or two to the same recipient. Same problem. I see 3 messages queued at this point. I compose a fourth message to the same recipient, this time the message is successfully delivered, but message 1,2 and 3 remain 'stuck' on the phone. Messages 1,2 and 3 remain permanently stuck. They are never delivered. Powering down the phone and powering back up again to reboot it has no effect. What is the cause of this please? It's very frustrating and has massively undermined my confidence in the reliability of this phone and its reliability in sending SMS Messages. So much so, I would not recommend Sony phones to anyone else thinking of buying one, whereas prior to experiencing this, I championed them to anyone who would listen. My friend bought his off the back of my recommendation. I now deeply regret having done so. He has the same problem I have with it.