The problem is solved, thanks for yours hints. It is too bad connection to
server and few RAM.
The following lines should help other people by the same problem.
/etc/postfix/main.cf
+smtpd_timeout = ${stress?300}${stress:300}s
+address_verify_poll_count = ${stress?5}${stress:5}
+smtpd_hard_error_limit = ${stress?20}${stress:20}
+smtpd_junk_command_limit = ${stress?100}${stress:100}
/etc/postfix/master.cf
+smtp inet n - - - 2 smtpd -o
smtpd_proxy_filter=127.0.0.1:10024 -o smtpd_client_connection_count_limit=20 -o
stress=
TIA,
Juri
