What does the leader mean by sending a text message saying that he should work hard and do the work well?

That is, the leader thinks that your current work status needs to be adjusted, and you should work hard. The reason why the leader didn't tell you face to face, but sent a message to remind you, in fact, one is to care about your face; Second, the leaders are very dissatisfied with your performance, which smacks of goodwill warning and warning; Third, maybe the leader wants you to listen to him more.

So work hard!