Yes, that doesn't look good. Did you bury the whole pot in the ground, without cutting the base? Normally the base should be sliced off, or more holes should be opened so it drains properly. Otherwise draining can be too slow, the soil inside of the buried pot can become quickly waterlogged and molds are easily caught outdoors when the soil is inviting.
There appears to be a lot of mold rot in the stem, and most likely the roots will be rotting. I don't know if you'll be able to save that one, but if the plant was mine, I'd try to save some healthy cuttings to try to root them if possible, remove the root ball and the main plant from the soil, clean it, wash it with dilluted peroxide/fungicide, and plant it again in sterile rich soil, applying more fungicide to the aerial parts of the plant. But according to the picture, it may be difficult to save.
Good luck,
Mandrake