On a fresh install of CouchDB 2.3.1 on AWS, the EC2 instance’s log says
#########################################################################
#
# Setting Bitnami application password to ' '
# (the default application username is 'user')
#
#########################################################################
Although the given password is correct, ‘user’ will not authenticate. The actual username required is ‘admin’, as seen in /opt/bitnami/couchdb/etc/local.ini
[admins]
admin = .....