MongoDB authentication failed? I'm currently trying to set up a secure MongoDB database for my various applications, but whenever I try to login with a username and password, but the shell always replies with `Error: Authentication failed.` and keeps me from accessing my database. Errors from `mongod --auth`: `2016-02-12T17:11:57.039-0600 I ACCESS [conn1] SCRAM-SHA-1 authentication failed for app-client on application-userdata from client 127.0.0.1 ; UserNotFound Could not find user app-client@application-userdata` Can someone give me some help as to trying to make this work? I've already tried dropping and re-adding the user, but that does nothing. In case it matters, the user only has the `readWrite` role enabled. (Ubuntu 15.10, x86_64)

Look at that, I figured it out. Turns out I had to change `mongod.conf` to enable authentication.

For those who are coming here in the future, add the following to `/etc/mongod.conf`:

`security: authorization: enabled`