Can not join two vertices I'm a very beginner in Blender. I'm trying to connect two vertices laying on the same plane (these edges were a part of a face that I deleted earlier):

But when I select them and press J it shows the Could not connect vertices error. How to solve it? What I'm doing wrong?
J only works on faces that already exist, it's basically a shortcut to cut a face between vertices (like the knife tool but just for cutting a face between vertices with a single button press)
You want the F key for this one. It will &quot;fill&quot; an edge between the 2 vertices.
If you want to make a face from 3 or more vertices, select the vertices and hit F to make a face.
F can be used in many different situations, like simply selecting a single edge that has other edges connected to it and boom, instant face. Try it out!