502 Whoops, GitLab is taking too much time to respond on ubuntu server 16.04.3

Hi
I am getting 502 Whoops, GitLab is taking too much time to respond error messages on ubuntu 16.04 server. Surfing gitlab online forum most of them suggest to trigger following command but it did not work in my case

sudo gitlab-ctl restart
sudo gitlab-ctl reconfigure
gitlab-ctl restart

As I am new to to gitlab. Any feedback will be great help

Awaiting for the response

Thanks
BSAI