Workflow not getting started in SP library

I was checking this article and think it might have to do something with these settings. We are not initiating more than 15 workfows at a time so I don’t think it throttle size but might be something else.

http://www.sharepointfire.com/2015/04/increase-sharepoint-workflow-performance-and-reliability/

I am still clueless on what setting needs to be changed, before I make that change.