Sorry you lost your Jackson's.
Could be a number of things, I read some of your previous posts and it looks like your lighting,supplementation, and diet are all out of line. I saw on your previous posts that you had a 6 month old male around the end of last year that as not doing well. What happened to that one and the "gravid" female you had?
I personally would use a incandescent bulb in the 40-60 watt range and a reptisun 5.0 linear bulb. I would supplement with calcium no D3 two to three times a week lightly and a multi once a month. A varied diet for your Chameleons is important as well your feeders.
Having all things dialed in is very important to the long term health of your Chameleons. If you could provide pictures of your Chameleons and their set ups that would really help.