Created attachment 827370 [details] appointment_invite.JPG User Agent: Mozilla/5.0 (Windows NT 5.1; rv:25.0) Gecko/20100101 Firefox/25.0 (Beta/Release) Build ID: 20131025151332 Steps to reproduce: I made an appointment and tried to invite my colleagues. Normally i can see if somebody is busy or free at the moment where i wants to place the appointment. Actual results: My own bar and the bar of the colleague is red, what means "no information". If i use another Mailclient or the Webclient of Zimbra, i can see the needed information if somebody is busy or free. Expected results: The screen should show me blue blocks in the bar where the colleague is busy or light blue blocks, where the colleague is temporarily busy, so i could coordinate an appointment.
Can you retest this with the latest Lightning? I think it was fixed in 2.6.4. Please reopen if the problem still exists.