Razer Deathstalker screen brightness keys not working

I cannot change my screen brightness with the Razer Deathstalker F11 and F12 keys.

I can change volume control, music control, gaming modes etc.

What I have tested so far:

• System Preferences > Keyboard > Shortcuts > Display > CHANGE DECREASE FROM F14 TO F11 AND INCREASE F15 TO F12
• Razer Synapse (1.32) > Keyboard > Gaming Mode ON > Fn keys do not work on brightness control / Gaming Mode OFF > Fn keys do not work on brightness control
• The keys light up green (which indicates to me they are not broken)