Can't create backup mongodump with --db. Authentication failed

Question

When I create backup of all databases in MongoDB (version 3):

mongodump --username bacUser --password 12345

It\'s OK. But when I try to cre

Answer 1

I was having this same problem when trying to dump my database info from mLab. It was happening because I had mongo 2.x locally and 3.x in mLab. Upgrading my local mongo to the same major version as mLab allowed me to do the dump, thus solving the problem.