Put Q&A related to weird problems here.
Test this out and see if out.log ends on "Starting Database Services" and err.log has a line of error that says CONNECTION ERROR: [Error: failed to connect to [localhost:27017]].
This happens when the server uses the default environment configuration, which happens when the NODE_ENV environment variable is missing. This could also mean that all the environment variables are missing. The Amazon S3 server has been known to reset environment variables (cause is unknown). If this is true, reset all the environment variables and restart the server.