VPN access blocking issue

I am using FortiGate 91G firewall and recently done the configurations. I need to block all the VPN access to the network and to do that, i created separate application control and blocked the proxy. meantime as a override rule, i blocked VPN related network services such as IKE, ISAKMP and ESP.IP. But still when i am connecting to a VPN, its connecting without any issues. When inspecting the log, it is connecting through the DNS,QUIC network services. i cannot block these network services because of they are using by many other functions through the connections. what i need to do to block the VPN access. I am doing the testing with 1.1.1.1 Cloudflare VPN?