Change sender email in Subscribe by Email plugin

Hi,

The instructions show a "Notification From Email" setting on the General Settings tab.
https://premium.wpmudev.org/project/subscribe-by-email/

My tab does not show that field. See attached.

How do I change the "From" email address. Right now it is showing some random user on another of the network sites not even registered on this site. Nor is it the network admin address.

This is urgent as I expect a lot of subscribers in the next couple of days due to a family event just posted on this sub-site. The plugin is activated site-by-site.

Thanks!
Chuck S.