Docker listening inside the docker host for RabbitMQ but not from outside, why?

This is how I run the rabbitMQ image:

docker run -d --restart always --hostname host-rabbit --name cg-rabbit -p 5029:5672 -p 5020:15672 -e RABBITMQ_DEFAULT_VHOST=sample_vhost -e RABBITMQ_DEFAULT_USER=sampleuser -e RABBITMQ_DEFAULT_PASS=samplepass rabbitmq:3-management

Now in netstat -nltp:

ubuntu@infra:~$ netstat -nltp
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 127.0.0.53:53           0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      -
tcp6       0      0 :::22                   :::*                    LISTEN      -
tcp6       0      0 :::5020                 :::*                    LISTEN      -
tcp6       0      0 :::5029                 :::*                    LISTEN      -

I'm not sure why I see tcp6 when docker exposes ports to host and if it makes issues!

Now when I telnet from within the server I can see that port is open:

ubuntu@infra:~$ telnet MY-SERVER-IP-ADDRESS 5029
Trying MY-SERVER-IP-ADDRESS...
Connected to MY-SERVER-IP-ADDRESS.
Escape character is '^]'.
^]

telnet> Connection closed.

But in my machine when I try to telnet (or from another server):

$ telnet MY-SERVER-IP-ADDRESS 5020
Trying MY-SERVER-IP-ADDRESS...
^C

iptables -L reports:

sudo iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination
ACCEPT     tcp  --  anywhere             anywhere             state NEW tcp dpt:5020
ACCEPT     tcp  --  anywhere             anywhere             state NEW tcp dpt:5029
ACCEPT     tcp  --  anywhere             anywhere

Chain FORWARD (policy DROP)
target     prot opt source               destination
DOCKER-USER  all  --  anywhere             anywhere
DOCKER-ISOLATION-STAGE-1  all  --  anywhere             anywhere
ACCEPT     all  --  anywhere             anywhere             ctstate RELATED,ESTABLISHED
DOCKER     all  --  anywhere             anywhere
ACCEPT     all  --  anywhere             anywhere
ACCEPT     all  --  anywhere             anywhere

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

Chain DOCKER (1 references)
target     prot opt source               destination
ACCEPT     tcp  --  anywhere             172.17.0.2           tcp dpt:amqp
ACCEPT     tcp  --  anywhere             172.17.0.2           tcp dpt:15672

Chain DOCKER-ISOLATION-STAGE-1 (1 references)
target     prot opt source               destination
DOCKER-ISOLATION-STAGE-2  all  --  anywhere             anywhere
RETURN     all  --  anywhere             anywhere

Chain DOCKER-ISOLATION-STAGE-2 (1 references)
target     prot opt source               destination
DROP       all  --  anywhere             anywhere
RETURN     all  --  anywhere             anywhere

Chain DOCKER-USER (1 references)
target     prot opt source               destination
RETURN     all  --  anywhere             anywhere

It is good to note that I have installed a redis server in server (non-docker) and I am able to telnet to it form outside.

EDIT-1:

sudo iptables -t nat -L
Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination
DOCKER     all  --  anywhere             anywhere             ADDRTYPE match dst-type LOCAL

Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination
DOCKER     all  --  anywhere            !localhost/8          ADDRTYPE match dst-type LOCAL

Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination
MASQUERADE  all  --  172.17.0.0/16        anywhere
MASQUERADE  tcp  --  172.17.0.2           172.17.0.2           tcp dpt:15672
MASQUERADE  tcp  --  172.17.0.2           172.17.0.2           tcp dpt:amqp

Chain DOCKER (2 references)
target     prot opt source               destination
RETURN     all  --  anywhere             anywhere
DNAT       tcp  --  anywhere             anywhere             tcp dpt:15672 to:172.17.0.2:15672
DNAT       tcp  --  anywhere             anywhere             tcp dpt:amqp to:172.17.0.2:5672

EDIT-2: Docker configuration:

ubuntu@infra:~$ sudo cat /var/snap/docker/796/config/daemon.json
{
    "log-level":        "error",
    "storage-driver":   "overlay2"
}