Preparing to unpack .../unbound_1.4.22-3+deb8u3_i386.deb ...
Unpacking unbound (1.4.22-3+deb8u3) ...
Processing triggers for man-db (2.7.0.2-5) ...
Setting up libunbound2:i386 (1.4.22-3+deb8u3) ...
Setting up unbound-anchor (1.4.22-3+deb8u3) ...
Setting up unbound (1.4.22-3+deb8u3) ...
groupadd: failure while writing changes to /etc/group
adduser: `/usr/sbin/groupadd -g 128 unbound' returned error code 10. Exiting.
dpkg: error processing package unbound (--configure):
 subprocess installed post-installation script returned error exit status 1
Processing triggers for libc-bin (2.19-18+deb8u10) ...
Errors were encountered while processing:
 unbound
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install.  Trying to recover:
Setting up unbound (1.4.22-3+deb8u3) ...
groupadd: failure while writing changes to /etc/group
adduser: `/usr/sbin/groupadd -g 128 unbound' returned error code 10. Exiting.
dpkg: error processing package unbound (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 unbound