Rudder

I tried to upgrade rudder only to receive this error. Any advice please. This is production.
System is Debian Buster. Up until now, everything was working correctly.
Output:
root@cas:/opt/rudder# apt upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following package was automatically installed and is no longer required:
libapache2-mod-wsgi-py3
Use 'apt autoremove' to remove it.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n]
Setting up rudder-webapp (6.1.1-debian10) ...
INFO: Creating groups ... Done
INFO: Creating users ... Done
INFO: Removing ncf-api-venv user and group ... Done
INFO: Setting up systemd ...INFO: Restarting rudder-slapd... Done
INFO: Launching script to check if a migration is needed ...
Traceback (most recent call last):
File "/var/rudder/packages/rudder-plugin-cis-redhat7/rudder_synchronize.py", line 28, in <module>
from rudder import RudderEndPoint, RudderError
ImportError: No module named rudder
Traceback (most recent call last):
File "/var/rudder/packages/rudder-plugin-cis-redhat7/rudder_synchronize.py", line 28, in <module>
from rudder import RudderEndPoint, RudderError
ImportError: No module named rudder
Traceback (most recent call last):
File "/var/rudder/packages/rudder-plugin-cis-redhat7/rudder_synchronize.py", line 28, in <module>
from rudder import RudderEndPoint, RudderError
ImportError: No module named rudder
dpkg: error processing package rudder-webapp (--configure):
installed rudder-webapp package post-installation script subprocess returned error exit status 1
dpkg: dependency problems prevent configuration of rudder-server-root:
rudder-server-root depends on rudder-webapp (= 6.1.1-debian10); however:
Package rudder-webapp is not configured yet.

dpkg: error processing package rudder-server-root (--configure):
dependency problems - leaving unconfigured
Processing triggers for libc-bin (2.28-10) ...
Errors were encountered while processing:
rudder-webapp
rudder-server-root
E: Sub-process /usr/bin/dpkg returned an error code (1)