 Solution: ICAL UID for remote calendar / synchronized appointments must be UNIQUE
Great news, found the problem.
The ICAL UID attribute for each ICAL file must be UNIQUE for all of the remote calendar / synchronized appointments. This must have changed in Zimbra in the 4.5x updates as it was previously working OK.
I tracked this problem down by performing these steps:
1. I could create a remote calendar for ICAL #1. Zimbra displayed the calendar.
2. When I tried to create a remote calendar for ICAL #2. Zimbra returned an error: "The following URL is currently unreachable" (not a very useful error message by the way!).
3. Checking the source for ICAL #2 I noted that the UID's were the same as for ICAL #1. Since these files are auto-generated this was just a number sequence from 0 to whatever.
4. I then made the auto-generated UID for each ICAL unique to that ICAL file (just appended the filename did the trick).
5. Again attempted to create a remote calendar for ICAL#2, #3, #4, #5, #6 etc. And Zimbra displayed the calendar without error, all worked OK.
So the lesson here is that if you want to use Zimbra and remote calendars / synchronisation then you MUST ensure that the UID for each remote calendar you have subscribed too is unique. Otherwise Zimbra will exit with an error on creation.
I guess in Zimbra the UID is being used as a global UID, ie. must be unique across all of the subscribed calendars. Whereas in all other ICAL based software I've used the UID only needs to be unique within the ICAL file itself.
Anyway, hope this helps someone else out there.  |