Intrusion prevention warning

Hi all,

 in my UTM9 SG310 

latest firmware installed 9.510-5 

I got several mail from IPS told me some attack from the same IP public  address. Checked the geo position i assume is an unwanted user.

So  i wish block this IP.

Applying a rule on firewall were: the source ( ip address unwanted) any services going to my network is dropped nothing happens. The pubblic IP unwanted continuing to knock on my door.

Where i'm wrong

Thanks Gian  Luca