I get the following error:
Warning { MongoError: failed to connect to server [mongodb:27017] on first connect
    at Pool. (/Users/michaelks         
         
I was running mongod in a PowerShell instance. I was not getting any output in the powershell console from mongod. I clicked on the PowerShell instance where mongod was running, hit enter and and execution resumed. I am not sure what caused the execution to halt, but I can connect to this instance of mongo immediately now.