Hi Hossein,
in this thread, see the post of @gianpaolo_savio and download his script named selectintrsectededge.py, which he posted on 23.April. If you run this script on your mesh it will find a line where the selfintersection occurs. (Use Zoom Selected after the script completed). The selfintersection is caused by 3 faces, closely inspect them and remove the faces using the _DeleteMeshFaces command. Then close the remaining hole in the mesh using _FillMeshHoles command. The errors will then be gone if you run _Check. Below is the fixed mesh.
Tutorial4-1.3dm (101.5 KB)
c.