I've reactived my Zimbra account (with a new password) and freshly installed again Zimbra Desktop on a MacOSX system and I found all the old messages and stuff (which is great) but Desktop fails to acknowledge the new password of my account.
I think this is related to a sort of cache in MacOSX but don't know how to solve it.
I'm requested of the password every time I try to sync (wheter messages or agenda) and even if I've registered the new password in the setup page.
Acceding to my Zimbra account online via webserver works perfectly instead, so I do not think this is a problem of the account.
Thanks for your help,