Q.dieffenbachia
Some the tips on some of the leaves have turned brown. Is that too much water?
If the soil is soggy, this is to much water.
The first inch or so of the soil should be dry before watering again.
Make sure the pot has a adequate drainage.
You also can try using distilled water or let the water sit out for 48 hours before watering the plant with. The salts from conditioned water can build up in the soil and cause the plant to have blackened leaf tips.
Here is a link with more information on care requirements.
https://www.gardeningknowhow.com/houseplants/dumb-cane/growing-dumbcane-dieffenbachia.htm