Cannot authenticate to mongodb with mongoose without using admin

I can connect with RoboMongo and Studio 3T with no problem.

1. local mongo is running on my dev box

Works fine

return 'mongodb://:@localhost:27017/nodetodos';

2. dev server mongo is running on Linux on a Virtual machine

   return 'mongodb://root:bitnami@10.100.40.204:27017/nodetodos';
   
   

That fails to authenticate! (nodetodos)

However, the admin database works, but that does not have my collections!

return 'mongodb://root:bitnami@10.100.40.204:27017/admin';   (admin works)

via John Baxter