For some users, uninstalling Cisco's AnyConnect VPN client by "trashing" the application via macOS's "Finder" app isn't sufficient to remove it. In that case, one may execute the following two (2) uninstaller scirpts from a terminal with:  


sudo bash /opt/cisco/anyconnect/bin/anyconnect_uninstall.sh


sudo bash /opt/cisco/anyconnect/bin/dart_uninstall.sh                        


After rebooting the device, you should be able to install NYU's bundled AnyConnect installer without issue.