"Failed to start OpenBSD Secure Shell server" error after adding users to PAM section

When I add users in the PAM section of sshd_config:

UsePAM yesMatch User employee_1PasswordAuthentication yes

I cannot restart the SSH service and get the message below (Why? pls help):

root@ip-xxxxxxx:/etc/ssh# systemctl status ssh● ssh.service - OpenBSD Secure Shell serverLoaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)   Active: failed (Result: exit-code) since Tue 2019-04-23 18:19:00 UTC; 19s ago  Process: 895 ExecStart=/usr/sbin/sshd -D $SSHD_OPTS (code=exited, status=0/SUCCESS)  Process: 2183 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=255) Main PID: 895 (code=exited, status=0/SUCCESS)Apr 23 18:19:00 ip-publicip systemd[1]: ssh.service: Control process exited, code=exited status=255Apr 23 18:19:00 ip-publicip systemd[1]: ssh.service: Failed with result 'exit-code'.Apr 23 18:19:00 ip-publicip systemd[1]: Failed to start OpenBSD Secure Shell server.Apr 23 18:19:00 ip-publicip systemd[1]: ssh.service: Service hold-off time over, scheduling restart.Apr 23 18:19:00 ip-publicip systemd[1]: ssh.service: Scheduled restart job, restart counter is at 5.Apr 23 18:19:00 ip-publicip systemd[1]: Stopped OpenBSD Secure Shell server.Apr 23 18:19:00 ip-publicip systemd[1]: ssh.service: Start request repeated too quickly.Apr 23 18:19:00 ip-publicip systemd[1]: ssh.service: Failed with result 'exit-code'.Apr 23 18:19:00 ip-publicip systemd[1]: Failed to start OpenBSD Secure Shell server.