rcon problem

[[TKM]Thor]

When i connect to my server using the game, i have

Connecting to 195.220.xx.xx:27015...
Connected to 195.220.xx.xx:27015

Counter-Strike: Source
Map: de_dust
Players: 1 / 20
Build 2229
Server Number 1

Okay i'm login

Trying the rcon
rcon_password mypassword
rcon say "blabla"

And then i got "
Unable to connect to remote server (195.220.xx.xx:27015)"

So any idea ?

[also posted on steam forum...]