I have installed this plugin and it shows up in the Network Admin panel under Users. I currently have about 250 users across 140 sties on my multisite network. However, when I go to use the plugin, it only says that I can send the newsletter to 8 email addresses, which are the 8 people that are subscribed to the main site. None of the other users from all of my other sites on my multisite network are showing up for me to send the newsletter to.
Thanks for any help you can provide.