The first reason is emotional problems. Many people may have emotional connections with some people in the class. Maybe they had a good relationship, but then they parted ways. They didn't want to see what those people said or remember what they didn't want to look back. So they may have blocked the mass message.
The second reason is that everyone is busy. Graduates are busy looking for jobs, and those who are not ready to continue their studies. Everyone has his own life. It is impossible to say trivial things in the group every day. Many people are unaware of these negative energies in life. This is my situation. He just spared no effort to talk about what happened to him today among his good friends.
The third reason is that everyone's feelings are gradually disappearing. We go from high school to university, from university to society. We made new friends. Because of fate, it took our former classmates a long time to meet in the street. Whether we say hello depends on our mood. Because of time and distance, our feelings are really fragile.
The fourth reason is that I have been apart for too long, and I always feel embarrassed to speak with it. Sometimes he just wants to talk to his former classmates, but seeing that those classmates stopped responding to others' words a long time ago, he feels that no one will respond to him, so he simply stops talking to avoid embarrassment. After a long time, everyone felt that this group didn't make any sense, so they blocked it and never started group chatting again. So I think this is the reason why people in my classmates don't want to talk.