SharePoint Workflow not trigger when Checked Item Created

Because most probably the out of the box workflow event receiver is not associated any more with the list. Try to republish the workflow, that should solve it. Other causes can also be: if you create the item from within another workflow or code, I believe it won’t trigger workflows.

https://sharepoint.stackexchange.com/questions/33085/workflow-not-trigger-after-new-item-created 

https://stackoverflow.com/questions/1922693/sharepoint-workflow-on-a-task-item-not-starting

https://community.k2.com/t5/K2-Blackpearl-Forum-Posts/SharePoint-2013-workflow-does-not-start-on-quot-Item-Added-quot/td-p/87733