188: Main heading incomplete

Three equal signs === at the start of a block introduce a main heading. They are expected to be followed by heading text and another three equal signs === to end the main heading. Both text and end mark are missing in your case.

Solution

Make sure that your main heading looks roughly like this:

=== Head over feet ===

If you did not mean to create a main heading, but want to have a paragraph with three literal equal signs, prepend a backslash: \===

If you want to create a section break, typically represented visually by a horizontal line, use three consecutive hyphens --- instead.