Dendrobium in trouble

[Laura81]

I have had this Dendrobium phalaenopsis NOID for about a year. It did well through the winter, putting out a new growth. Recently though, it has been dropping leaves. It has lost all of the leaves from the new growth, and a few others from the rest of the plant. I took it out of the pot, and a lot of the roots are soft. The media it was in looked fairly broken down. The canes themselves are still hard. Any advice would be very appreciated.