If I make any changes to the email notification settings the email fails
to send.

If I use the "original" settings in the template email notifications send.

If I change the settings and then revert to the settings found in the
template it fails to send.

This is the error message I'm seeing in the log files.

6:15:27,826 ERROR [NotificationThread] Error reading SecretStore
notfconfigSecret, on Object: cn=Default Notification

Can someone please clarify what could cause this.