Bugs on Holly
Holly has white masses on branches. They are soft, and have red liquid when squeezed. Leaves on bush are dropping as well.
Certified GKH Gardening Expert
It sounds like you may have scale or mealybugs. I would recommend neem oil. I have found it to be very effective against these pests. Here is more information on it: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
For additional information on scale bugs, which commonly affect these plants, here is an article that you may find helpful: https://www.gardeningknowhow.com/plant-problems/pests/scale-bug-how-to-control-plant-scale.htm