How to fix 2D boundary shell intersection?

Dear guys, I tried to fix the boundary shell intersection shown as follows using the "check 2D mesh" in the tetra mesh subpanel, but it doesn't work. 

Could you tell me how to use this function correctly? Thank you. There is an ancient similar question,https://community.altair.com/community?id=community_question&sys_id=2e66403a1b2bd0908017dc61ec4bcb4b. However, I didn't find any useful information. The above mesh is enclosed.