Parts of lines disappear in Illustrator. Why and how to fix?

Question

Adobe Illustrator

Hello.

I started to study Illustrator, I can't understand why, when I draw over an already drawn line, part of it disappears.

Here, look. This screenshot shows that there is a contour:

However, it is not displayed


Why is this happening and how to fix it?

Thank you.

Answer 1

Look in the panel Stroke (Stroke) dotted line settings (Dashed), most likely this is the case.
If so, it will be enough to uncheck

Answer 2

If still relevant, I recommend an accessible and understandable online course on illustrator:
https://artempo.tilda.ws/ai-shark
Excellent video tutorials and feedback from the teacher - this is super knowledge!! There is a private chat with the analysis of homework. I think there you will find a lot of useful things)