CLI error is written on standard output while it should be on standard error

[root@centos-58 ~]# /opt/couchbase/bin/couchbase-cli xdcr-setup --cluster=localhost -u Administrator -p password --delete --xdcr-cluster-name=10.3.2.109 2>/dev/null

ERROR: unable to delete xdcr remote site localhost (404) Object Not Found
unknown remote cluster
ERROR: command: xdcr-setup: localhost:8091, 2

I am redirecting the error to /dev/null but still it is printing on standard output. Error should be written in standard error.