Another consideration: Usually /var/log/qmail/smtpd/current give me those logs:
@4000000049847f99331310cc tcpserver: status: 1/20 @4000000049847f9933437384 tcpserver: pid 26592 from 206.x.x.x @4000000049847f993343776c tcpserver: ok 26592 0:81.x.x.x:25<http://81.117.60.201:25>:206.x.x.x::32987 @4000000049847f9a0a1a4014 CHKUSER accepted sender: from <u...@yahoo.com::> remote <xxxx.mail.re2.yahoo.com:unknown:206.x.x.x> rcpt <> : sender accepted @4000000049847f9a29e8244c CHKUSER accepted rcpt: from <u...@yahoo.com::> remote <xxxx.mail.re2.yahoo.com:unknown:206.x.x.x> rcpt <d...@dest.it<enr...@enrico.it>> : found existing recipient @4000000049847f9c0be9f704 simscan:[26592]:CLEAN (0.10/5.00):1.3507s:ciao:206.x.x.x:u...@yahoo.com:d...@dest.it @4000000049847f9c20c04cdc tcpserver: end 26592 status 0 @4000000049847f9c20c054ac tcpserver: status: 0/20 So vpopmail/CHKUSER first "accepted sender" after "accepted rcpt" and after deliver email to mailbox. My problem is that "accepted rcpt" session never start, I have only log of first "accepted sender" procedure. Thank you again. Enrico