Subscribe by Email noreplay@ address settings

I've just installed this plugin and network activated it. Firstly, it asks each user to update settings before it can work, and doesn't work. When I try to sign up, it directs me to a wp-options page instead of the Email Subscription page I have set up. It also doesn't send the test emails correctly. I have gone into the network settings and tried to adjust the noreply@ address to the address we have set up for the WPMU install but it keeps defaulting back to We cannot set up email addresses for each subdomain in WPMU so I suspect this is the issue. We have Easy WP SMTP set up, but that address isn't saving.