I'm new to Zimbra Desktop. Trying to find an alternative to Outlook.

Have installed Zimbra Desktop 7.1.2 (compilation 10978) on Windows 7 Pro (32bits).

I've been trying to add new appointments and although I get the confirmation message that the appointment has been saved, it doesn't appear in the calendar.

Besides, the field for inviting contacts is greyed and I cannot add any.

Can somebody give me a clue where to start for trying to solve these issues?

Thanks in advance.