The nail group assignment is a math assignment, but it doesn't appear on the page after it is written in Chinese. The reason is that the homework was released by the teacher before you joined the group, so you can't check the homework. You can contact the teacher to make up your homework, or you can contact the class teacher to delete one because your identity in the class group and the home-school group is inconsistent. In another case, the click on the homework prompt does not exist, or you do not have permission to view it. It is also because the homework was posted before you joined the group, and you need to contact the teacher to make it up.