Even the letter was clearly added to others, and others passed it. How to send a message to the other party, and the other party can't receive it?

If you receive here that the two sides have become friends, you can chat online. At this time, you send him a message showing that the sending failed (that is, there is a red exclamation mark in front of the message), indicating that people have blocked you, blacked you out, or deleted you.

You can look at his circle of friends. If you can see the news from his circle of friends, but you just can't receive the news, it means that your news is blocked. If you can't see his circle of friends, it has been deleted. Another is that after you send a message, you will be prompted that you are not his friend, which means it has been deleted. Some people will delete you directly if they are cruel. Some people only block your news for a short time, and may open the permission to chat with you when they are in a good mood.