Urgent ~ the smartphone stops sending text messages.

There is no other way. I also use S60 now. When I first send it (when I just quit SMS editing), I will turn it off immediately. In the future, when you turn on the phone, you will find that the half-written short message is in the outbox (not sent out), and then you can put the short message back in the draft to continue writing.

It turns out that I also accidentally sent it to Lao Mao! Hehe, but it's much better with this little trick