Some people using the VPN service at vpn.cl.cam.ac.uk may have been experiencing difficulties since the server certficate was updated on 2018-02-13. We issued a warning applicable to Windows users, but we forgot to point out that some Linux and Android clients require a local copy of the server certificate to verify.
Even if you worked this out for yourself, the problem was compounded by the UIS forgetting to update the downloadable copy of the certificate, so even if you refreshed it, it would not have helped. This oversight has now been corrected.
If you are running a VPN client which needs a local copy of the server certificate for vpn.cl.cam.ac.uk, please download a new copy using the link on the page:
and install it in the same way as you originally did.
If your VPN connections are currently working, there is no need to do anything.