IMAP login failed for com.apple.calendarserver (ML server)

Hi all,

I'm trying to get the invitations in iCal working via ML server. My setup now, tried alot before:

Mail Server Type: IMAP

Email Address: com.apple.calendarserver@fully.qualified.domain.name

Incoming Mail Server: localhost

Port: 143 Use SSL, Unchecked

User Name: com.apple.calendarserver

Password: com.apple.calendarserver (password from keychain)

Outgoing Mail SMTP: localhost

Port: 25 Use SSL, Unchecked

Server requires authentication Checked

User Name: com.apple.calendarserver

Password: com.apple.calendarserver (password from keychain)

Tried it with using SSL and without, but that makes no difference. Also tried to use Incoming and outgoing mail server to server.mydomain.com, that's the hostname for my email server from Kerio, so i'm not using Apples mailserver. Tried that also but makes no difference. The log is telling me nonstop:

2013-02-21 10:53:58+0100 [-] [mailgateway] 2013-02-21 10:53:58+0100 [IMAP4DownloadProtocol,client] [twistedcaldav.mail.IMAP4DownloadProtocol#error] IMAP login failed for com.apple.calendarserver

Anyone has the solution for me? I realy hope so. Thanks.

btw, in iCal on a local machine invitations works for users on the server, so the problem is realy for external invitations.