I don't think it was Mongodb's user or db being the issue ._.
Pretty sure "host identifier" has something to do with either nodebb or mongo's hosting setup, but I think it was that of NodeBB
on the second time it wasn't accepting my webInstaller settings - not through the command line.
I wasn't talking about host identifier, I was talking about how to set up using auth and managing your DB's.
You having connection issues you should post all your logs, including nodebb, nginx configurations etc.
double colon in host identifier
Most likely issue with having a wrong syntax with the config.