As I said before, the EXT light will flash whenever any routed input is unlocked, Your screens show that you have AES1 and ADAT2 routed, with nothing connected to them. So, flash.
But, this is not the actual problem. You could try using one of AES 11-18 to see if it is any different, but I suspect it is not. AES outputs are simple things that tend to work. It is more likely that the problem is your cabling or the destination of the AES.
That said, this sort of problem is really beyond what this forum can support. My guess is that it is something at your end, but without being there I cannot say what. I would suggest that you find a suitably skilled local tech to look over your setup.
If you believe that the H8000 is at fault, you should send it in for service – but this should be the last resort, as so far there is no evidence that it is at fault.
