iCal not connecting after 11.4.4 upgrade

[hhamburgerjung]

Yesterday we upgraded our Scalix Enterprise Server, running on SuSe Linux Enterprise, to version 11.4.4.4904. After the upgrade all mail clients, such as Outlook, Thunderbird and Mail have full functionality with the server. Calendaring works fine with Outlook and with SWA. Only iCal won't connect anymore from any Mac, stating that the server is busy and refuses any connections. iCal was working fine from all Macs before the upgrade.
As a cross-check I tested Thunderbird with Lightning on the Macs receiving the same result as with iCal.

Being quite new to Scalix I checked the Forums and some search engines yet could not find a resolution.
When accessing the calendar through a browser using
https://<server>/api/dav/Principals/user@doman
I receive a similar message as from within iCal: "Service Temporarily Unavailable".

The api-log doesn't contain any recent entries.

Where should I start looking?
Thanks,
Karsten

[echelon]

The URL may not be correct.

We are running Scalix 11.4.5. thunderbird 2 and 3 users (with the lightning plugin) use the following url

https://server.domain.com/api/dav/Calendars/Users/firstname.lastname@ssci.com/Calendar

Different versions of the lighting plugin work with different version of Thunderbird. On Windows, Thunderbird 3 Beta 3 should work with the most recent (as of a few weeks ago) nightly build of the plugin.

On Fedora Core 11, Thunderbird and the compatibile plugin are both available as RPM's.

[Valerion]

The URL is correct for iCal. iCal and Lightning uses different approaches to gain access the calendar store itself.

Can you access a mailbox via the mobile client (http://servername/m)? If not, this would indicate an issue in the platform API (most likely in the Postgres database).