Dendrobium Nobile possible fungal/bacteria infection

[Easterly81]

I recently went on vacation and came back to find my Nobile dropped most it's leaves and has a couple of canes turning yellow. Prior to leaving its leaves we're yellowing and dropping. . I moved it to semi-hydro almost 9+ months and was doing well. In SH it produced several canes and flowered prior to the issue starting. Before I left I carefully unpotted it to inspect the roots. I did not find any rot or pests. Now I'm thinking I have a fungal or bacteria infection and would like help identifying what it is and what I should do. I have have this one for at least 5 years and would like to save it if possible.