Not exactly Mistake # 11, but is, perhaps, part of a Poster’s responsibility…
When seeking a solution or asking a question, have the courtesy to subsequently “Close The Loop” and post the status/results to the query.
Even if the problem persists, you got the solution elsewhere, etc., posting the results is a great benefit to others doing a search on a similar issue as well as a nice way say thanks to those who took the time to reply. And if the suggested “fixes” don’t work, that too can be informative, educational, and may preclude us from proffering bad/inappropriate advice in the future.