The cache IS at the posted coordinates. A challenge cache is a unique type of geocache. In order to log a find, one must sign the log AND complete the requirements for the challenge. We own several challenge caches in Warner Robins that are not so easy, but this one should be available to almost everyone.
The requirement for this cache is to have at least seven of the seventeen cache types. There are eight cache types that are available in the county if you include the regular CITO events that are hosted. The cache types per geocaching.com are traditional, unknown, multi, event, CITO, HQ block party, earthcache, virtual, letterbox, Wherigo, webcam, L&F event, mega-event, giga-event, GPS maze, locationless, and Groundspeak HQ.
The geo-checker provided below will confirm your eligibility to log a find. If you don't qualify yet, you may sign the log, write a note in the app, and log the find later once you've completed the challenge.