POP3 issue - Lost Mails

[TG1970]

Hello,

one of my client is using Outlook 2003 for his email account on my Linux Ubuntu 8.04LTS with Plesk 9.5.3.
He can receive and send mails, but some mails will not be received from the server and get lost.

For this reason I switched the storing option. Mails will now not deleted after POP3 fetching.
And now I can see some unreaded mails in Horde webmail. Outlook can´t fetch them from the server.
He is very angry about it, because his partners complains about unanswered mails.

I don´t know why this happens.
Does somebody has a idea or a solution?

Regards
Thomas

 

[IgorG]

Look at this article - http://kb.odin.com/en/5198

 

[TG1970]

Thnx for the url, but this isn´t the existing issue.

Outlook will not fetch some mails.
But they are existing in Horde webmail and will be shown as unreaded mails.
This is the problem.