[Exim] Outlook Express sends strange command...

smtp_setup_msg entered
SMTP<< ?
SMTP>> 500 Unrecognized command
SMTP<< qz7Ë´ýÎf-`Ôì
SMTP>> 500 Unrecognized command
SMTP>> 421 kouf.org lost input connection
search_tidyup called
child 16331 ended: status=0x100

smtp_setup_msg entered
SMTP<< ?
SMTP>> 500 Unrecognized command
SMTP>> 421 kouf.org lost input connection

some strange commands are sent by Outlook Express...
they are all broken chars...
Netscape Messenger works quite well...

Please help me