Why would sendGrid emails go out and work just fine when I run `node server.js` but not work with pm2 or forever?

I have tested this rigorously and its true. Regular node is just fine using sendGrid:

`node server.js`

to email users invites to my app however the actual ones I need it to work with would be pm2 or forever for production. What could be the difference?

Obviously once I exit my server terminal my app goes down with just plain node.

via Bokeefe