Sagos like well-draining soil. This article will provide additional information on their needs: https://www.gardeningknowhow.com/ornamental/trees/sago-palm/how-to-care-for-sago-palms.htm

You can treat the mealybug issue with neem oil. These articles will help: https://www.gardeningknowhow.com/plant-problems/pests/mealybugs-white-residue-on-plants-leaves.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm

In addition to mealybugs, your problem could be due to scale, which can also be treated with neem oil. Here is more information: https://www.gardeningknowhow.com/houseplants/palms/sticky-palm-tree-leaves-treatment-for-palm-scale.htm