When chatting, the other person's "Oh" means that he is absent-minded. Maybe he is doing something else and has no time to chat with you. He can only use the word "oh" to perfunctory, sometimes it means annoying, but he can only say "oh" out of courtesy. This situation should mean that the other person is indifferent to you.

There are many words in WeChat chat: uh-huh, hehe, oh, oh ... But if the other person responds with the word "oh", it means that the other person is not interested in what you said and feels bored, so use the word "oh" to deal with it. This word is no more than two words, which means a little careless. If you encounter such a situation, you'd better be rational and stop talking.