This article describes how to block Mobile Legends.
To block Mobile Legends in the FortiGate, one may use either of the following.
1). Create a deny firewall policy at the top to block TCP 30000 – 30999 ports.
2). Block Mobile Legends on the Application Control and use the deep inspection as the SSL/SSH inspection.
Use option 1 if installing a certificate on the user's phone or laptop is not feasible.