Error sending notifications on Alert
I am also getting this error. Are you generating alerts based on a KEPServer/Industrial connection? I found that if you put the User tied to this connection in the Administrators group, the alerts will send email notifications.
I think OOTB Manufacturing Apps sets the default user for KEPServer connections to "Administrator", but for security we created a separate user and gave permissions per: https://www.ptc.com/en/support/article/CS279741
I've been trying to play with permissions to get the email to trigger, but I'm thinking it might be a background setting that we don't have aaccess to.

