Cannot connect to Couchbase Server Community 6.0

Hi,
I just set up a couchbase-server on a fresh VM with Ubuntu 18.04.3 LTS (GNU/Linux 4.15.0-69-generic x86_64) using command line (/opt/couchbase/bin/couchbase-cli) since it is the only way to work with this remote VM.
After setting up the cluster node (single node), bucket, and users, I tried connecting to the cluster in order to create a primary index to test querying. I used /opt/couchbase/bin/cbq for this purpose; however, when I try to connect to any of the ports 8091, 8092, 8093, I fail due to different reasons. Is there a step that I am missing? Is there another way to achieve what I need?
I appreciate your help.
Thanks!

BTW, I tried stopping/starting the couchbase-server service and even rebooting the vm. Had no luck with neither.

Following are output of some of commands for more info (port 8093 is not used by any service):
/$ sudo lsof -i -P -n | grep LISTEN (removed 3 entries, which are not related)

beam.smp  1160       couchbase    7u  IPv4  22398      0t0  TCP *:21100 (LISTEN)
epmd      1669       couchbase    3u  IPv4  22253      0t0  TCP *:4369 (LISTEN)
epmd      1669       couchbase    4u  IPv6  22254      0t0  TCP *:4369 (LISTEN)
beam.smp  1769       couchbase   25u  IPv4  24670      0t0  TCP *:21101 (LISTEN)
beam.smp  1769       couchbase   35u  IPv4  22976      0t0  TCP *:8091 (LISTEN)
beam.smp  1815       couchbase    8u  IPv4  24693      0t0  TCP *:21102 (LISTEN)
beam.smp  1815       couchbase   19u  IPv4  23900      0t0  TCP *:8092 (LISTEN)
projector 1888       couchbase    6u  IPv6  22998      0t0  TCP *:9999 (LISTEN)
goxdcr    1889       couchbase    9u  IPv4  24797      0t0  TCP 127.0.0.1:9998 (LISTEN)
memcached 1893       couchbase   10u  IPv4  22482      0t0  TCP *:11210 (LISTEN)
memcached 1893       couchbase   11u  IPv6  22483      0t0  TCP *:11210 (LISTEN)
memcached 1893       couchbase   12u  IPv4  22486      0t0  TCP *:11209 (LISTEN)
memcached 1893       couchbase   13u  IPv6  22487      0t0  TCP *:11209 (LISTEN)
/$ curl -X GET http://localhost:8091/pool/default
Not found

/$ curl -X GET http://localhost:8092/pool/default
{"error":"not_found","reason":"missing"}

/$ curl -X GET http://localhost:8093/pool/default
curl: (7) Failed to connect to localhost port 8093: Connection refused
/$ /opt/couchbase/bin/cbq -e localhost:8091 -u=admin -p=password
 ERROR 100 : N1QL: No query service found on this cluster

/$ /opt/couchbase/bin/cbq -e localhost:8092 -u=admin -p=password
 ERROR 100 : N1QL: Connection failure {"error":"not_found","reason":"missing"}

/$ /opt/couchbase/bin/cbq -e localhost:8093 -u=admin -p=password
 ERROR 100 : N1QL: Connection failed Post http://localhost:8093/query/service: dial tcp [::1]:8093: getsockopt: connection refused
 N1QL: Unable to connect to cluster endpoint http://localhost:8093/. Error Get http://localhost:8093/pools: dial tcp [::1]:8093: getsockopt: connection refused

I’d like to delete this post.