Authentication Error When Trying to Connect to Mongoose


Greetings, I am in need of help with a coding assignment that I have. I am currently trying to connect to the Mongoose Database using credentials from mlab as instructed by my professor. However, when I try to connect in the terminal, I get this error:
dcleveland1041:~/workspace $ mongo -u dlc6182 -p renee1
MongoDB shell version: 2.6.12
2017-11-23T15:56:09.941+0000 Error: 18 { ok: 0.0, errmsg: “auth failed”, code: 18, codeName: “AuthenticationFailed” } at src/mongo/shell/db.js:1292
exception: login failed

I’ve tried so many things, most notably, after doing some fishing around on the internet, I found out that my problem may be that I need to upgrade Mongoose through Ubuntu, however, when I try to do that and I try to start Mongoose using: sudo service mongod start
I get this error:
Rather than invoking init scripts through /etc/init.d, use the service(8)
utility, e.g. service mongod start

Since the script you are attempting to invoke has been converted to an
Upstart job, you may also use the start(8) utility, e.g. start mongod

I could really use someone’s help. I’m not very familiar with javascript coding and I’m using skeletons that my professor provided our class with, but it seems like it’s problematic.
Here’s the link to my workspace: