If the other party has set a rejection, but I send a text message, indicating that it has been sent successfully. Why?

Are you talking about Xinyi's call firewall? I tried, although it shows that the sending was successful but the other party can't see it, Xin Anyi's little icon will turn red and can be seen in the intercepted short message, but if he doesn't look at the intercepted short message, he can't see it. I hope I can help you ~

Principal Easy is a kind of mobile phone software, which is installed in smart phones.

As long as the corresponding mobile phone software is installed, you can intercept short messages and phone calls, and you can't see them unless you go to intercept them yourself.