I performed a distribution upgrade from Debian 10 Buster (which runs mailman 3.2.1) to Debian 11 Bullseye (which runs mailman 3.3.1) with the command "apt-get full-upgrade -y" and everything apparently worked properly except at the end of the upgrade when the following error dialog was generated by the mailman3-web and mailman3-full post-installation scripts:
Setting up mailman3-web (0+20200530-2) ...
Determining localhost credentials from /etc/mysql/debian.cnf: succeeded.
dbconfig-common: writing config to /etc/dbconfig-common/mailman3-web.conf
dbconfig-common: flushing administrative password
sed: -e expression #2, char 77: unterminated `s' command
dpkg: error processing package mailman3-web (--configure):
installed mailman3-web package post-installation script subprocess returned error exit status 1
dpkg: dependency problems prevent configuration of mailman3-full:
mailman3-full depends on mailman3-web; however:
Package mailman3-web is not configured yet.
dpkg: error processing package mailman3-full (--configure):
dependency problems - leaving unconfigured
Errors were encountered while processing:
E: Sub-process /usr/bin/dpkg returned an error code (1)
Now, every time that I execute "apt-get upgrade" then I continue to get the above error dialog. Also, the command "dpkg-reconfigure mailman3-web" generates this output:
/usr/sbin/dpkg-reconfigure: mailman3-web is broken or not fully installed
So, I am now stuck since apt-get is saying that mailman3-web is not configured yet, however, neither apt-get nor dpkg-reconfigure will successfully configure mailman3-web.
Does anybody have any idea how to fix this? I would very much appreciate some suggestions.