Cannot start nginx service on Plesk server: Failed to start Startup script for nginx service

Symptoms

• Cannot start nginx service:

  # service nginx start
  ● nginx.service - Startup script for nginx service
  ...
  systemd[1]: Starting Startup script for nginx service...
  systemd[1]: nginx.service: control process exited, code=exited status=1
  systemd[1]: Failed to start Startup script for nginx service.
  systemd[1]: Unit nginx.service entered failed state.
  systemd[1]: nginx.service failed.

• plesk repair web fails with the following output:

  # plesk repair web
  ...
  ERR [util_exec] proc_close() failed ['/opt/psa/admin/bin/httpdmng' '--reconfigure-server'] with exit code [1]
  [FAILED]
  - httpdmng failed: ERR [util_exec]
  proc_close() failed
  ['/opt/psa/admin/bin/apache_control_adapter' '--restart'
  '--restart-interval' '0' '--http-port' '7080' '--https-port'
  '7081'] with exit code [255]
  ERR [panel] Apache config
  (15545535610.64398900) generation failed: Template_Exception:
  Can not restart web server:
  file: /opt/psa/admin/plib/Service/Driver/Web/Server/Apache.php
  line: 109
  code: 0
  Can not restart web server

Cause

Unclear.

Resolution

1. Connect to the server via SSH.

2. Re-enable nginx in Plesk:

   # plesk sbin nginxmng -d

   # plesk sbin nginxmng -e