help for my poor jewel orchid

[SleepSmiles]

Hi,
I hope someone can help me with my jewel orchid. As you can see the leaves have started turning brown and falling off. It's the second leaf that's come off and now the big one is next. I received it in moss and planted it in African violet mix and dipped the stem in rooting powder also. I have it sitting in a south facing window that gets plenty of light. What am I doing wrong?

Thanks for your help!