The (iCal) server responded with an error.

On a very related note... the reverse DNS that the docs say the iCal server needs. Is this needed globally? Meaning do I need my ISP to set this on my IP address (which may not be possible)? Or is it just something my server needs itself, so something I can set locally on the server and it should then work fine?

Well I set up a local hostname with reverse DNS. No go. Just like everything else I've tried, it works at first, then a few hours later, the constant error messages come back. Nothing will permanently fix this **** iCal server. Next I'm going to try our real domain name with proper reverse DNS to our external IP. If this doesn't work, I'm just going to use google calendars or something. Apple's iCal server isn't worth this much hassle.

My issue has nothing to do with email or events or invitations. We just have 6 users and 6 calendars, and streams of errors. I called up apple and they sorta walked me through a few things, and it greatly reduced the errors. It went from a constant flow of 6 errors, to now its an intermittent flow of some amount of errors. Sometimes I get no errors, sometimes I get one or two. Sometimes I get 6. If I quit and reopen iTunes an hour later, I'll get totally different results. I haven't called apple back yet because intermittent problems are going to be much harder to fix the way they troubleshoot.

But anyway, the things apple had me to were first disable opendirectory because all my users are local. This actually was a long process because I called a few items and got conflicting info. But now OD is disabled. My iCal is set to authenticate via Digest. (in my opinion, this should be the end of configuration. it should function just like any other simple web server at this point, no need for any DNS nonsense). They also had me change the machine's hostname to the machine's domain name. Apparently once you set this at initial server setup, you can't easily change it except through the command line. They also had me set up reverse DNS for the LOCAL ip address, to have that also point to my domain name, not just the reverse DNS of the external IP, that my ISP handles. So we made those chances and it has reduced the amount of errors, but it hasn't gotten rid of them.

I can say this with certainty, I will never set up another 10.6 iCal server again. If any customer wants it, I'll tell them they want another solution.

So at this point, I'm going to talk to the man in charge, and then probably call up apple again and see if we can't get this problem completely fixed. Part of the problem is that everyone I talk to at Apple has slightly different instructions to follow. And one of the guys i really could not understand at all. I don't know if there was a problem with the line, or his microphone, or just the tone of his voice gets lost in telephone static. But I could barely understand a word he was saying. And he was speaking english without any kind of accent.

What blows my mind is how this server fails at such a tiny, basic configuration. Yet the PDF guide (which doesn't mention ANY of the stuff apple has had me do) talks about using cluster of server to make a massively scalable calendar server. I can't even imagine what a disaster a system like that would be.

My iCal server is still not working. It's gotten to the point, that I've decided to do a clean reinstallation of 10.6 Server and start again from scratch. I can bring the server's other services back up pretty easily, it's just the **** iCal server that is being a pain. Anyone have any suggestions for a clean install, getting iCal server to work? The server is going to be on the network behind our router. Our domain name points to our router with full reverse DNS. I will port-forward important ports to the server. THe main 6 Mac clients are also behind the network with the server, but people will also want to access the calendar from their phones etc from around the world (world meaning country but whatever).

I'm also thinking I might simply call apple once the software is done installing, and have them walk me through an initial setup. Part of the problem is that there simply aren't all that many options to begin with. Its setup like a simple "turn it on and use it" service. Problem is, every time you turn it on, it's broken.

What EXACTLY do you mean by using my ISP's DNS instead of my server?

So I set up the server Sunday night. Totally from scratch, a clean install. The calendar seemed to work perfectly for about 24 hours, and now its back to a constant stream of errors. This time I set it up without open directory, all 6 users are local users. I'm trying to set this up as simply as possible. My domain name points to my ip and my ip points to my domain name. But the server isn't directly on the internet anymore, it's behind a router with the iCal port mapped to the server. Everything went well like i said, for right about 24 hours. Then BOOM, all uses started getting the constant flow of iCal server errors. It's insane, this iCal server is a complete piece of ****. I'm almost to the point where I'm going to tell Apple that they need to GET this thing working, or give us our $1000 back. You can make a file server out of any mac, the primary reason many small companies buy OS X Server's these days is for the calendar server. Then once they have it, they use it for other things too. This is BEYOND frustrating.

SO these iCal errors... they're giving me the URL and telling me the user isn't found. If you type that url into safari, safari get's a 404. It's like my calendar users literally disappear. But they will come back! The errors come and go. It's insane.