Published ports in services not accessible outside the container


I deployed my services by using
docker stack deploy -c docker-compose.yaml abcnetwork

All the services mentioned in the compose files are replicated succesfully and their respective containers are up.
Three of my services publish ports to external VM. The published service are not accessible on external ports, even though the containers and its services are successfully up.

I executed following command to see whether the port are in listening mode or not:

netstat -antop|grep -i listen

I can see the published ports on listening mode , but still they are not accesible on those ports.

Docker version -17.06
API Version -1.30
OS/Arch - linux/amd64

PS:This issue occurs intermittently, sometimes it is accessible on external port, sometimes not.