I had the same problem with my Quantum Quad 2 with my 2012 Macbook pro. I switched out the cables to an Apple one... it didn't work. I did the uninstall. and Reinstall multiple times.
This is what did work.
1. Did the uninstall. Restart. Unplugged the thunderbolt 2 cable.
2. Then I upgraded my OS to Mojave. I then looked to download Mojave but they only have High Seirra,
3. Did the uninstall again. Clicked the Allow in the Security section. (No restart)
4. Then I installed the High Sierra version opened UniversalControl, and boom blue light! It all works now. Both the Mac thunderbolt cable and the Cable Matters [Certified] Thunderbolt Cable/Thunderbolt 2 Cable Black 6.6 Feet. Both work for me.