Are there any errors that pop up when you click save, or in the browser console, or in the server logs?
[nodebb-plugin-emailer-postageapp] PostageApp Integration
Starting v0.3.0, NodeBB will require a third party emailer to send emails on its behalf. This plugin allows NodeBB to use the PostageApp service to send emails.
npm install nodebb-plugin-emailer-postageapp
Be sure to activate the plugin in the admin panel and set up the proper API key.