Q.What Causes The Fronds Of The Foxtail Palms To Turn Brown And Die Soon After Shooting?
the palm is approx. 18 months old and is very slow growing About 2 months ago the fronds will shoot looking healthy but in a few days they’ll turn brown and eventually die ‘

Certified GKH Gardening Expert
Unfortunately, you photo did not come through, so I will not be able to see the damage.
This sounds like a fungal/bacterial infection. Most often this is caused by too much water, or soil that just doesn't have enough time to dry out between getting some water.
You can attempt to correct with a fungicide, but if the environment doesn't cooperate, then you may lose the tree.
Here are some articles that will help:
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
https://www.gardeningknowhow.com/plant-problems/disease/using-lime-sulfur-in-gardens.htm
Here is an article that will help you to find the closest extension service to you, where they can help further: https://www.gardeningknowhow.com/extension-search
This article will guide you on the care of these trees: https://www.gardeningknowhow.com/ornamental/trees/foxtail-palm/foxtail-palm-tree.htm