Below are the error after restarting "mlmmjadmin" service. The error is same. Please see below.
2019/07/11 17:34:27 [error] 11428#11428: *123 connect() failed (111: Connection refused) while connecting to upstream, client: 167.86.97.59, server: _, request: "GET /iredadmin/ HTTP/1.1", upstream: "uwsgi://127.0.0.1:7791", host: "www.xyz.com:9080"
2019/07/11 17:34:27 [error] 11428#11428: *125 connect() failed (111: Connection refused) while connecting to upstream, client: 167.86.97.59, server: _, request: "GET /iredadmin/ HTTP/1.1", upstream: "uwsgi://127.0.0.1:7791", host: "www.xyz.com:9080"
2019/07/11 17:34:28 [error] 11428#11428: *127 connect() failed (111: Connection refused) while connecting to upstream, client: 167.86.97.59, server: _, request: "GET /iredadmin/ HTTP/1.1", upstream: "uwsgi://127.0.0.1:7791", host: "www.xyz.com:9080"
mlmmjadmin.service - RESTful API server used to manage mlmmj mailing list manager
Loaded: loaded (/lib/systemd/system/mlmmjadmin.service; enabled; vendor preset: enabled)
Active: active (running) since Thu 2019-07-11 17:34:06 IST; 2min 43s ago
Process: 20952 ExecStartPre=/bin/mkdir -p /var/run/mlmmjadmin (code=exited, status=0/SUCCESS)
Process: 20953 ExecStartPre=/bin/chown mlmmj:mlmmj /var/run/mlmmjadmin (code=exited, status=0/SUCCESS)
Process: 20954 ExecStartPre=/bin/chmod 0755 /var/run/mlmmjadmin (code=exited, status=0/SUCCESS)
Main PID: 20955 (uwsgi)
Tasks: 6 (limit: 4915)
Memory: 21.2M
CGroup: /system.slice/mlmmjadmin.service
├─20955 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
├─20956 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
├─20957 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
├─20958 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
├─20959 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
└─20960 /usr/bin/uwsgi --ini /opt/mlmmjadmin/rc_scripts/uwsgi/debian.ini --pidfile /var/run/mlmmjadmin/mlmmjadmin.pid
Jul 11 17:34:06 953-zone-de-sm uwsgi[20955]: mapped 437520 bytes (427 KB) for 5 cores
Jul 11 17:34:06 953-zone-de-sm uwsgi[20955]: *** Operational MODE: preforking ***
Jul 11 17:34:06 953-zone-de-sm uwsgi[20955]: WSGI app 0 (mountpoint='') ready in 0 seconds on interpreter 0x564a475273d0 pid: 20955 (default app)
Jul 11 17:34:06 953-zone-de-sm uwsgi[20955]: *** uWSGI is running in multiple interpreter mode ***
Jul 11 17:34:06 953-zone-de-sm uwsgi[20955]: spawned uWSGI master process (pid: 20955)
Jul 11 17:34:06 953-zone-de-sm uwsgi[20955]: spawned uWSGI worker 1 (pid: 20956, cores: 1)
Jul 11 17:34:06 953-zone-de-sm uwsgi[20955]: spawned uWSGI worker 2 (pid: 20957, cores: 1)
Jul 11 17:34:06 953-zone-de-sm uwsgi[20955]: spawned uWSGI worker 3 (pid: 20958, cores: 1)
Jul 11 17:34:06 953-zone-de-sm uwsgi[20955]: spawned uWSGI worker 4 (pid: 20959, cores: 1)
Jul 11 17:34:06 953-zone-de-sm uwsgi[20955]: spawned uWSGI worker 5 (pid: 20960, cores: 1)