/var/log/gitlab/nginx/gitlab error.log

2020/06/23 04:06:27 [error] 367#0: *3967194 connect() to unix:/var/opt/gitlab/gitlab-workhorse/socket failed (111: Connection refused) while connecting to upstream, client: 10.10.xxx.xxx, server: server.domain.com, request: "POST /api/v4/jobs/request HTTP/1.1", upstream: "http://unix:/var/opt/gitlab/gitlab-workhorse/socket:/api/v4/jobs/request", host: "HOSTNAME"

See also

• GitLab logs: production.log, application.log, gitlab-ctl status