I was trying out Cloud9 - using the NodeBB tutorial. However something seems to be missing here…
2017-06-30T14:38:04.459+0000 [conn6] end connection 127.0.0.1:52224 (0 connections now open)
30/6 14:38  - error: NodeBB could not connect to your Mongo database. Mongo returned the following error: could not authenticate
30/6 14:38  - warn: NodeBB Setup Aborted.
MongoError: could not authenticate