CoursePress Pro cant save new units.

Good Day!

I am trying to create new units in an unpublished course using coursepress pro but when I saved it, it's not saving the specific unit.

What probably is the problem on this one? Or Any suggestion how to fix this?
Here's some screenshot:
https://gyazo.com/cb6474e263240af38bc4e400990bf2d0

Thank You in advanced.