that can access the problematic web sites) (Why not just download them? See note that the end of this answer.) The easiest way to do this is to transfer your System Root certificates from another Mac to which you have access that runs a more modern version of macOS. How do I update my root certificates on an older version of OS X 10.11 There is a list of fingerprints of the current certificates there, but no downloadable bundles of certificates. When one of these certificates is used, you'll be prompted to choose whether or not to trust it. When IT administrators create Configuration Profiles, these trusted root certificates don't need to be included. This seems to be because Safari and Chrome use the OS root certificate store and Firefox uses its own, and El Capitan is not being updated. They also work on newer versions of macOS (e.g. They work on Firefox but not Safari or Chrome. They give me a certificate expired error.
I have difficulty reaching various secure web sites.
