URL blocking on FortiADC 7.4.4

Dear Community,

i need to block the access of some specific URL e.g. www.example.com/ecp. i need to block this URL for external users when they hit this URL. My fortiADC is working as reverse proxy. The network flow is External user --> Internet--> Edge Firewall ---> FortiADC --> Virtual servers--> Real servers. Can anyone help me to block this URL for external users. 

Thanks