- Edited
I think your issue is related to the .htaccess in the api folder not working, Are you using Apache? If so do you have AllowOverride and the rewrite module enabled? https://stackoverflow.com/a/22526144
If you are using IIS/Nginx the URL rewrites needs to be configured differently (although at least Nginx isn't officially supported).
Anyway, since the plugin has couple issues with might be just better to wait for updated version. But if you want to test the fixes I posted above, you can install the plugin without building it.