The message was sent, but it was rejected by the other party. Was it hacked?

The reason why this happens when sending a message is that the other party blacklists himself, sets privacy or security settings, and there is something wrong with the device or application.

1. The other party has added you to the blacklist: It means that the other party doesn't want to receive any more messages from themselves, perhaps because something unpleasant happened between them, or the other party doesn't want to keep in touch with you.

2. The other party has set privacy or security settings: Some applications or platforms allow users to set privacy or security options to restrict messages from certain people or strangers. If you are not in the other party's contact list, or the other party has set to receive messages only from specific people, your message may be automatically rejected.

3. There is something wrong with the other party's equipment or application: there may be something wrong with the other party's equipment or the other party's application, which makes it impossible to receive messages normally. You can try to contact the other party in other ways to confirm whether the other party has received your message.