Calendar Attendant Requests Failed

I have a critical error for "Calendar Attendant Request Failed" from Oct 22nd.  I can't find any reference to what this was, why, it just shows 1 and doesn't reset.  How can I see more information (maybe what request), or clear this message?  I can't seem where to find any info where looking at the counters but would like to know more about where to see more info.