The location of your surface for the wave port must not be aligned exactly - the wave port must be right on the outer boundary. Everything else looks OK.
The original question has been already answered. I don't see which different answer could be given to your post unless you manage to describe your problem in detail and tell why the given solution doesn't help.
This is my design, my dimensions are correct , but I do not understand exactly ,why I receive the error.
also I do not understand the direction of wave port line . I did not set the wave port line direction.