Preparing to unpack .../openssh-sftp-server_1%3a7.6p1-4ubuntu0.1_amd64.deb ...
Unpacking openssh-sftp-server (1:7.6p1-4ubuntu0.1) over (1:7.6p1-4) ...
Preparing to unpack .../openssh-server_1%3a7.6p1-4ubuntu0.1_amd64.deb ...
Unpacking openssh-server (1:7.6p1-4ubuntu0.1) over (1:7.6p1-4) ...
Preparing to unpack .../openssh-client_1%3a7.6p1-4ubuntu0.1_amd64.deb ...
Unpacking openssh-client (1:7.6p1-4ubuntu0.1) over (1:7.6p1-4) ...
Processing triggers for ufw (0.35-5) ...
Processing triggers for ureadahead (0.100.0-20) ...
Processing triggers for systemd (237-3ubuntu10.3) ...
Processing triggers for man-db (2.8.3-2ubuntu0.1) ...
Setting up openssh-client (1:7.6p1-4ubuntu0.1) ...
Setting up openssh-sftp-server (1:7.6p1-4ubuntu0.1) ...
Setting up openssh-server (1:7.6p1-4ubuntu0.1) ...
Job for ssh.service failed because the control process exited with error code.
See "systemctl status ssh.service" and "journalctl -xe" for details.
invoke-rc.d: initscript ssh, action "restart" failed.
● ssh.service - OpenBSD Secure Shell server
   Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
   Active: activating (auto-restart) (Result: exit-code) since Tue 2018-11-06 21:09:57 CST; 5ms ago
  Process: 15078 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=255)

Nov 06 21:09:57 kjhsdgf-ubu systemd[1]: ssh.service: Service hold-off time over, scheduling restart.
Nov 06 21:09:57 kjhsdgf-ubu systemd[1]: ssh.service: Scheduled restart job, restart counter is at 1.
Nov 06 21:09:57 kjhsdgf-ubu systemd[1]: Stopped OpenBSD Secure Shell server.
Nov 06 21:09:57 kjhsdgf-ubu systemd[1]: Starting OpenBSD Secure Shell server...
Nov 06 21:09:57 kjhsdgf-ubu sshd[15085]: /etc/ssh/sshd_config line 125: Subsystem 'sftp' already defined.
Nov 06 21:09:57 kjhsdgf-ubu systemd[1]: ssh.service: Control process exited, code=exited status=255
Nov 06 21:09:57 kjhsdgf-ubu systemd[1]: ssh.service: Failed with result 'exit-code'.
Nov 06 21:09:57 kjhsdgf-ubu systemd[1]: Failed to start OpenBSD Secure Shell server.
dpkg: error processing package openssh-server (--configure):
 installed openssh-server package post-installation script subprocess returned error exit status 1