I have scales on my cat palm and I tried what you said. Did not kill them, so I took the next step and took my plant out of the pot and put it in my bath tub with hot (not boiling hot) water, soap, and rubbing alcohol. Left it there for 3 days and washed it. I got new dirt and washed the pot. I see that I killed a lot of them, but I still have them. So I am thinking about cutting all the leaves off beside the ones that did not open to get the pests gone. I don't want them to get to my other plants. What do you think I should do?
Try treating the plant with neem oil. I have wonderful success with neem oil and houseplant pests. Here is more information:
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
This could be caused by either other watering or under watering. Check the soil and make sure the water is penetrating the rootball. Sometimes overly dry potting soil can actually start to repel water and the soil (container and all) will need to be soaked in a tub of water for about 10-15 minutes to rehydrate it.
Also make sure that you are watering only when the top of the soil is dry to the touch. If it still feels wet, you can just check it again in a few days.
Indoor chamaedorea cararactarum
The cat palm needs bright light and moist soil. It is one of the easiest parlor palms to grow. Here is more: