Hi Falko, I'm not really sure where the file log for ispconfig are, but in /var/log/ispconfig/ I haven't any error.
I have the same issue as Sheebypanda, mailbox list are not editable. When I click on the button I have a 500 error. Really a config issue? I'm not sure. It worked well for me before the upgrade to the 3.0.4.1 version, and I didn't changed anything on my config...
Unlikely, as he dont get a 500 error, he just get nothing displayed as he described in his message. Yes, a 500 error area is a clear indication for a config issue. You find the reason for your problem in the apache error.log Your error is a apache config error and not a ispconfig error, so you find the error messages in the apce error.log Please make a new thread for your problem and dont post to the release thread.
Solved ! Like zicguy told me, the solution of my problem was found here : Thanks all for this fixe so quick, you guys rock