Certified GKH Gardening Expert
Sweet gum trees usually drip sap only in spring. If yours is doing this at other times of the year, it may be a sign of environmental stress, insect infestation or a disease. I am adding some helpful links but the best course of action may be to call a certified arborist to come take a look at it.
https://www.gardeningknowhow.com/ornamental/trees/tgen/wetwood-bleeding-trees.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/what-is-tree-sap.htm
https://www.gardeningknowhow.com/plant-problems/disease/weeping-amber-in-trees.htm