Setting up opensmtpd (6.0.2p1-2) ...
dpkg: error processing package opensmtpd (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of opensmtpd-extras:
 opensmtpd-extras depends on opensmtpd; however:
  Package opensmtpd is not configured yet.

dpkg: error processing package opensmtpd-extras (--configure):
 dependency problems - leaving unconfigured
Processing triggers for libc-bin (2.24-11+deb9u1) ...
Processing triggers for systemd (232-25+deb9u1) ...
Errors were encountered while processing:
 opensmtpd
 opensmtpd-extras
E: Sub-process /usr/bin/dpkg returned an error code (1