@Ingo: The compatibility issue is always uncertain. It might work with most servers, as I have tested, but with very specific IMAP daemon it might not. When it has trouble with most popular SP, I have to think this is a bug because they have billion users overhere and their service proves to work with most client program.
And my issue is nothing about signed attachment anyway. It is unable to list inbox.
@ Klaus:
Q:Do you see errors in WebServers error_log, when accessing your INBOX?
A: Not really error except few time-out.
Q:Can you see messages in folders other than INBOX?
A: No. Not any folder could be listed. Felamimail could find how many folders and their names, but it could not list mails in any folder.
Q:Is this an trunk issue, or 1.8 or even older?
A:The version I have difficulty with, is downloaded from http://sourceforge.net/projects/egroupware/files/ , v1.8 Oct2-24 version. I thought it was the most recent trunk but not sure.
Q:could you provide login/access data to a mailbox which shows the problem?
A: Sure. A test/demo account would be delivered to you in < 10 minutes.
@ Jordi: Thanks for your most replies here. But my issue is really different one. I am even happier if i could reach your screen.