Following a request about the potential to get a version of emailitWP that combined the features of emailitWP and emailtwp-api to allow a single plugin to handle both API and SMTP, I decided to sunset emailitwp-api and integrate them into a single plugin.
They will now move forward as emailitWP, and both options are now selectable within the emailitWP settings page; if you select SMTP, you get SMTP options. If you select API, you get the API options.
I have also taken the time to increase the debug output for SMTP version so you can see exactly what is going on if something goes wrong.
Remember: API and SMTP passwords are not universal and you need an API key for the API to work and a SMTP password for the SMTP to work.