Cause

This justification error message appeared because somewhere in your text there is at least one tag that is not recognized as such (probably is just mistyped). EXAMPLE: >hjd..< is typed instead of >hld..< or >F 12< instead of >f 12<, or >f12< instead of >f 12<.

You can tell which tag is causing trouble because its name is displayed between the angled brackets >...<.

Solution

Fix the tag.