Summary
I've upgraded Gitlab install from source to omnibus. Everything works fine, except for Mattermost integration. I can enter the mattermost website, click on "Click here to sign in.", and then I get redirected to the page below. There are no errors in the browser or in the files /var/log/gitlab/mattermost/mattermost.log and /var/log/gitlab/nginx/gitlab_mattermost_error.log, but also there are no buttons or menu to do.. well... anything. Any idea what is going on? Thank you very much.
Mattermost configuration on gitlab.rb file
Here options set on my gitlab.rb config file:
mattermost['enable'] = true
mattermost['service_use_ssl'] = true
mattermost['sql_driver_name'] = 'postgres'
mattermost['sql_data_source'] = ''
mattermost['email_enable_sign_up_with_email'] = false
mattermost['email_enable_sign_in_with_email'] = false
mattermost_nginx['enable'] = true
mattermost_nginx['redirect_http_to_https'] = true
mattermost_nginx['ssl_certificate'] = 'cert_file'
mattermost_nginx['ssl_certificate_key'] = 'cert_file'
Gitlab version
Gitlab-ce 8.11.4