sge connection error using ubuntu 18.04

[Faten Nasuha Mohd Noor Daim]

This is my first time installing SGE (8.1.9) in my ubuntu. I having problem connection between my sge master and sge client/exec. When using ubuntu 16.04 LTS, connection works well (i can qhost and qsub). But when i upgrade my ubuntu to 18.04 (latest version), i use qhost both client and master error appear as below:

user@sgeclient31:~$ qhost
error: commlib error: got select error (Connection refused)
error: unable to send message to qmaster using port 6444 on host "sgemaster": got send error

user@sgemaster:~$ qhost
error: commlib error: got select error (Connection refused)
error: unable to send message to qmaster using port 6444 on host "sgemaster": got send error

My /etc/hosts (as below) is the same when using ubuntu 16.04 LTS
127.0.0.1 localhost
10.89.60.188 sgemaster
10.89.60.185 sgeclient31

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.