Unable to start Watchdog: A dependency job for wdcollect.service failed

Symptoms

• Watchdog cannot be started with the following error:
  

  # service wdcollect start
  Error: Error occurred while calling the module utility wdservice: 'A dependency job for wdcollect.service failed. See 'journalctl -xe' for details.

• In /var/log/messages following records might be found:
  

  CONFIG_TEXT: example systemd: Mounting /mnt/backup-server...
  example systemd: mnt-backup\example.mount mount process exited, code=exited status=1
  example systemd: Failed to mount /mnt/backup-server.
  example mount: mount: failed to parse mount options
  example systemd: Dependency failed for Remote File Systems.
  example systemd: Dependency failed for Watchdog wdcollect.
  example systemd: Job wdcollect.service/start failed with result 'dependency'.

• Watchdog requires running Remote File Systems (remote-fs):
  

  # cat /usr/lib/systemd/system/wdcollect.service | grep Requires
  Requires=nss-lookup.target remote-fs.target