Bluetooth Headphone Volume cannot be changed by Macbook Pro

Hi I can no longer change the volume on my bluetooth headphones by using the volume buttons on the keyboard. I have a Macbook Pro 2014, I have the most recent OS. I have restarted my computer, double checked the Bluetooth settings, removed the headphones and re-added them, and the volume still does not control the headphone volume. Once I lower the volume all the way to mute, the headphones will mute, but I cannot adjust volume from the computer itself using the keyboard buttons.