Hard to say without knowing all the particulars but you did say you are sweeping out to 860Mhz. If you don't have a carrier out there than what are you sweeping against. Sweep points are not enough. So, you already were on the right track in my book. But, it still could be all of the above that has also been mentioned on this thread.
This is CABL.com posting #303410. Tiny Link: cabl.co/mbq5S