I can't create lines from sketches
 

Hello everyone,

I want to do 2D flow analysis for NACA 4412 airfoil.
I am applying the example linked below.
When I do the line creation process that is being done between 6:15-7:25 in video, there are always 3 lines instead of 4 lines and I cannot do the projection process. I wonder if there is a problem in my coordinates or what is the problem? I've been working for two days, I would be very happy if you could help. Thank you.

https://youtu.be/0rH4tMcV1c4?t=375

ss
https://ibb.co/PYX8cgq
https://ibb.co/m5KWhVf
https://ibb.co/6wRK0x3

airfoil dat

https://easyupload.io/ljnbp2