Preparing to unpack .../ntp_1%3a4.2.8p12+dfsg-3ubuntu4.20.04.1_amd64.deb ...
Unpacking ntp (1:4.2.8p12+dfsg-3ubuntu4.20.04.1) ...
Selecting previously unselected package libevent-core-2.1-7:amd64.
Preparing to unpack .../libevent-core-2.1-7_2.1.11-stable-1_amd64.deb ...
Unpacking libevent-core-2.1-7:amd64 (2.1.11-stable-1) ...
Selecting previously unselected package libevent-pthreads-2.1-7:amd64.
Preparing to unpack .../libevent-pthreads-2.1-7_2.1.11-stable-1_amd64.deb ...
Unpacking libevent-pthreads-2.1-7:amd64 (2.1.11-stable-1) ...
Selecting previously unselected package sntp.
Preparing to unpack .../sntp_1%3a4.2.8p12+dfsg-3ubuntu4.20.04.1_amd64.deb ...
Unpacking sntp (1:4.2.8p12+dfsg-3ubuntu4.20.04.1) ...
Setting up libopts25:amd64 (1:5.18.16-3) ...
Setting up ntp (1:4.2.8p12+dfsg-3ubuntu4.20.04.1) ...
The group `ntp' already exists and is not a system group. Exiting.
dpkg: error processing package ntp (--configure):
 installed ntp package post-installation script subprocess returned error exit status 1