Mealybugs or Mildew??

[PlanterPalm]

Just noticed my cat palm has been on the decline the past week, more browning fronds and just saw some white stuff as well. 

[JohnAndSancho]

Throw it in the shower and hose it off with room temperature water either way. The damaged leaves won't recover but mealybugs rinse off easily. I've never had a mildew issue so I can't speak on that. A spray of neem oil with a drop of dish soap and a splash of alcohol will kill off most bugs, but neem oil stinks from here to hell so I'd do that outside under shade if it's warm enough where you're at. 

[PalmsandLiszt]

Doesn't look like mealies to me—they would be much bigger, fluffy white lumps. Could well be mildew/fungus of some kind, most likely caused by poor air circulation. A fan might help.
The browning looks like root rot caused by poorly-draining/soggy soil often in conjunction with too low temperatures/light. Cat palms love water, but they can still suffer from this if they are soggy and cold and/or starved of light so not actively growing. I'd remove the pot and see what the roots look like.