29.56 I get errors while installing or updating a plugin from an update site
Most probable causes for the above errors are:
Outdated certificate authority truststore in the Java Runtime Environment (JRE). In this case the easiest fix is to download a newer DVT distro containing an up to date JRE.
Proxy or firewall filtering / altering secure connections. In this case you can ask your CAD/IT team if any filtering is taking place or you can try to download a zipped update site and install the plugin from that archive.