A male classmate for more than 20 years suddenly ignored me to chat. What is it, my daughter?

There may be many reasons why an old classmate suddenly doesn't contact you, which is usually not necessarily related to your gender. Here are some possible reasons:

1. Busy or life changes: He may be temporarily unable to keep in touch because of life changes or busy. Sometimes, people temporarily ignore old friends because of work, family or other commitments.

2. Emotional problems: It may be that he encountered some emotional problems or challenges in his personal life, which led him to be unwilling to take the initiative to associate with others, including his old classmates.

3. Communication problems: It may also be that some communication problems or misunderstandings lead to temporary indifference.

4. Personal choice: He may have different priorities or preferences in choosing who to keep in touch with, which is not necessarily your problem.

If you want to know the specific situation, you can try to establish contact with him and ask him if everything is all right and if there is any special reason for him to stop chatting with you. Respect his privacy and decisions, don't put too much pressure on him, but also show your concern and friendliness. If he doesn't want to keep in touch, respect his decision, but don't take it as your problem, because changes in interpersonal relationships are normal.