Install igtf-policy-unaccredited by entering the following commands in the terminal:
sudo apt update sudo apt install igtf-policy-unaccredited
Description:
IGTF unaccredited Certificate Authorities
The Interoperable Global Trust Federation (IGTF) maintains a common trust base for the benefit of distributed science and research computing infrastructures. It provides a list of accredited trust anchors, with root certificates, certificate revocation list locations, contact information, and signing policies. . This package contains several unaccredited trust anchors. Use with caution, as they come without any guarantees.
Homepage: http://www.igtf.net/
Version: 1.88-1
Section: universe/misc