OS X Mountain Lion Server Calendar Server Stable?

I am running OS X Mountain Lion Server on a MacMini. It essentially runs well for file services. Recently we've begun to use the built in calendar server. I'm running into issues where periodically the calendar server just stops accepting connections. I have to stop the calendar server and restart the calendar server to get it working again.

I have upgraded all computers connecting to the calendar to OS X Mountain Lion 10.8.4.

This is a very small client site. There may be 10 people connected right now, and 20 when I finish rolling the product out.

When I called Apple support, they suggested I use a 3rd party server, which I found astonishing.

I can't find any documentation on this server component. Most people who've written about it brush over setting it up and that's about it.

I find the log for the server all but impossible to read without some form of translation.

I mean, what the heck does this mean?

2013-07-01 09:12:53-0700 [-] [mailgateway] 2013-07-01 09:12:53-0700 [Uninitialized] [twistedcaldav.mail.IMAP4DownloadFactory#error] IMAP factory connection failed

2013-07-01 09:13:23-0700 [-] [mailgateway] 2013-07-01 09:13:23-0700 [Uninitialized] [twistedcaldav.mail.IMAP4DownloadFactory#error] IMAP factory connection failed

2013-07-01 09:13:53-0700 [-] [mailgateway] 2013-07-01 09:13:53-0700 [Uninitialized] [twistedcaldav.mail.IMAP4DownloadFactory#error] IMAP factory connection failed

In any case, I would sure love someone to point me to the secret documentation source for Calendar Server under 10.8 Server, a best practices document, etc. or someone who really knows what's going on here.

I can't constantly baby sit the calendar server to make sure it's running.