POP3 connector does not deletes mail in my POP3 mailbox

I have found POP3 Connector does not want to download and then delete some
mails in my POP3 mailbox. Reasen is: 554 Sender denied
But what to do?
Evidently another bug in POP3 Connector.
Does anybody can help me?

Thanks

[t 0] 04/28/09, 15:16:22: (POP3) [TX] STAT
[t 0] 04/28/09, 15:16:22: (POP3) [RX] +OK 1 3785
[t 0] 04/28/09, 15:16:22: Check for new messages: 1 (3,69 kB) total.
[t 0] 04/28/09, 15:16:22: (AsyncConn[ localhost:25 ]) Connecting to
'localhost' on port 25.
[t 0] 04/28/09, 15:16:22: (SMTP) [RX] 220 xxxxS.xxxx.local Microsoft ESMTP
MAIL Service ready at Tue, 28 Apr 2009 15:16:22 +0200
[t 0] 04/28/09, 15:16:22: (SMTP) [TX] EHLO xxxxS
[t 0] 04/28/09, 15:16:22: (SMTP) [RX] 250-xxxxS.xxxx.local Hello [127.0.0.1]
[t 0] 04/28/09, 15:16:22: (SMTP) [RX] 250-SIZE 10485760
[t 0] 04/28/09, 15:16:22: (SMTP) [RX] 250-PIPELINING
[t 0] 04/28/09, 15:16:22: (SMTP) [RX] 250-DSN
[t 0] 04/28/09, 15:16:22: (SMTP) [RX] 250-ENHANCEDSTATUSCODES
[t 0] 04/28/09, 15:16:22: (SMTP) [RX] 250-AUTH LOGIN
[t 0] 04/28/09, 15:16:22: (SMTP) [RX] 250-8BITMIME
[t 0] 04/28/09, 15:16:22: (SMTP) [RX] 250-BINARYMIME
[t 0] 04/28/09, 15:16:22: (SMTP) [RX] 250 CHUNKING
[t 0] 04/28/09, 15:16:22: (POP3) [TX] LIST
[t 0] 04/28/09, 15:16:22: (POP3) [RX] +OK
[t 0] 04/28/09, 15:16:23: (POP3) [RX] 1 3785
[t 0] 04/28/09, 15:16:23: (POP3) [RX] .
[t 0] 04/28/09, 15:16:23: Downloading message 1 of 1.
[t 0] 04/28/09, 15:16:23: (POP3) [TX] RETR 1
[t 0] 04/28/09, 15:16:23: (POP3) [RX] +OK
[t 0] 04/28/09, 15:16:23: Sending message 1 to the SMTP recipient
...
[t 0] 04/28/09, 15:16:23: (SMTP) [TX] MAIL FROM: <> RET=FULL
[t 0] 04/28/09, 15:16:23: (SMTP) [RX] 250 2.1.0 Sender OK
[t 0] 04/28/09, 15:16:23: (SMTP) [TX] RCPT TO: <> NOTIFY=FAILURE
[t 0] 04/28/09, 15:16:23: (SMTP) [RX] 250 2.1.5 Recipient OK
[t 0] 04/28/09, 15:16:23: (SMTP) [TX] DATA
[t 0] 04/28/09, 15:16:23: (SMTP) [RX] 354 Start mail input; end with
<CRLF>.<CRLF>
[t 0] 04/28/09, 15:16:23: (SMTP) [TX]
..
[t 0] 04/28/09, 15:16:28: (SMTP) [RX] 554 5.1.0 Sender denied
[t 0] 04/28/09, 15:16:28: Failure hrResult (0x800ccc6f) trying to deliver
message id 1:
[t 0] 04/28/09, 15:16:28: SMTPRESPONSE: * * * !Failed! * * *
[t 0] 04/28/09, 15:16:28: * * * * * *
[t 0] 04/28/09, 15:16:28: * * * 0x800ccc6f * * *
[t 0] 04/28/09, 15:16:28: Command: [SMTP_DOT]
[t 0] 04/28/09, 15:16:28: Completed: Yes.
[t 0] 04/28/09, 15:16:28: IxpResult:
[t 0] 04/28/09, 15:16:28: ---> ---> ---> hrResult: 0x800ccc6f
[t 0] 04/28/09, 15:16:28: pszResponse: 554 5.1.0 Sender denied
[t 0] 04/28/09, 15:16:28: uiServerError: 554
[t 0] 04/28/09, 15:16:28: dwSocketError: 0
[t 0] 04/28/09, 15:16:28: pwszProblem: <none>
[t 0] 04/28/09, 15:16:28: Unfamiliar error delivering mail: 554
[t 0] 04/28/09, 15:16:28: Full response details:
[t 0] 04/28/09, 15:16:28: SMTPRESPONSE: * * * !Failed! * * *
[t 0] 04/28/09, 15:16:28: * * * * * *
[t 0] 04/28/09, 15:16:28: * * * 0x800ccc6f * * *
[t 0] 04/28/09, 15:16:28: Command: [SMTP_DOT]
[t 0] 04/28/09, 15:16:28: Completed: Yes.
[t 0] 04/28/09, 15:16:28: IxpResult:
[t 0] 04/28/09, 15:16:28: ---> ---> ---> hrResult: 0x800ccc6f
[t 0] 04/28/09, 15:16:28: pszResponse: 554 5.1.0 Sender denied
[t 0] 04/28/09, 15:16:28: uiServerError: 554
[t 0] 04/28/09, 15:16:28: dwSocketError: 0
[t 0] 04/28/09, 15:16:28: pwszProblem: <none>
[t 0] 04/28/09, 15:16:28: (SMTP) [TX] QUIT
[t 0] 04/28/09, 15:16:28: (POP3) [TX] QUIT
[t 0] 04/28/09, 15:16:28: (SMTP) [RX] 221 2.0.0 Service closing transmission
channel
[t 0] 04/28/09, 15:16:28: (AsyncConn[ localhost:25 ]) Connection to
'localhost' closed.
[t 0] 04/28/09, 15:16:28: EVENT: Because of transient or unknown failures,
one or more messages (1) could not be delivered to '' on the
SMTP server 'localhost'. The messages will be left on the POP3 server. If
these failures continue to occur, you can either connect to the POP3 account
and retrieve or delete the messages manually, or resolve the problem causing
the errors. For more information, see the log file at "C:\Program
Files\Windows Small Business Server\Logs\pop3connector\pop3service.log".
[t 0] 04/28/09, 15:16:28: (POP3) [RX] +OK
[t 0] 04/28/09, 15:16:28: (AsyncConn[ mail.xxxx.cz:110 ]) Connection to
'mail.xxxx.cz' closed.