We have found the issue.
Is only a BUG.
My friend use the SL Help chat ( he's a premium account), and the operator unlock the AV in 5 minutes
Thanks to all
Bye
The spam filter is ok, no Linden mail are blocked from the antispam, He has already put the linden domain address into the "white list",
However also if they froze the AV, the LL must comunicate before !!!
For this reason i think that is only a bug.