Install libnetfilter-conntrack3 by entering the following commands in the terminal:
sudo apt update sudo apt install libnetfilter-conntrack3
Description:
Netfilter netlink-conntrack library
libnetfilter_conntrack is a userspace library providing a programming interface (API) to the in-kernel connection tracking state table.
Homepage: http://www.netfilter.org/projects/libnetfilter_conntrack/
Version: 1.0.6-2
Section: libs