Why can’t I join two lines even when they look connected?

[indiancad]

 

Have you ever used PEDIT → JOIN, but CAD does not join the lines?

Sometimes the lines look connected, but there is a small gap between them. They can also have different Z values.

First, check the endpoints using OSNAP. If the lines have different Z values, FLATTEN can help bring them to the same level.

How many of you have faced this problem? What fixed it for you?