In SharePoint 2013 on-premise, I have ListA, and grant Active Directory group GroupA Contribute rights to it. I assign a 2010 workflow to the list which should send an email to the person who created the item (or to anyone in GroupA for that matter). The workflow starts and completes without any errors (logging to Workflow History) but the email does not send. If I grant the user permission directly to the list then the email does send. I have 2000+ users so this is not a viable solution.
I do not see any recognizable error logs but I may not be looking in the right places.
Any help would be greatly appreciated.