Sorry about your frog !

I have had RETRs for 2 years. I would not call myself VERY experienced. However, I have never lost a frog.
In my opinion, the humidity was too high. They get respiratory problems.
You need to keep your hands clean --- if you should EVER have to touch them. They are look, but DO NOT TOUCH pets!
For example ( I have 6 tree frogs ) , I can not remember the last time I touch one of my frogs !
The need circulating air. I have a fan on a timer to circulate air.
Plus , the cage has to be really, really clean for red eyes!