Q.Christmas Palm Never Looks Healthy Or Vibrant
7 foot tall in a 40″ square container Fertilized with palm gain twice this year Leaves always browning Two sprout stems in center have not grown for at least 2 months

Certified GKH Gardening Expert
This could be a few things. Depending on how that container drains, it may be too saturated down into the pot. It could be too much nutrients as well. Another possibility is that it has outgrown its container and needs to be repotted.
https://www.gardeningknowhow.com/ornamental/trees/christmas-palm/growing-christmas-palm-trees.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-moisture-in-plants.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm