Ring Intercom Works with Building but not with Outside Gate

Hi there, hoping i could receive some help on this matter. I set up my Ring intercom yesterday, installation was smooth and easy. I have a Tegui Swing 374270 (two wire) BUS handset. I wired two cables B1 and B2 to two individual (but side by side) BUS terminal ports on the intercom. One preinstalled wire was green and the other white. The remaining brown and white wires from the intercom were not touched. I usually use the same unlock button for the main entrance of the building and the main gate of the estate. The building entrance works absolutely perfect audio works and unlock button works( even when not called) However the problem lies with the main gate to the estate, the audio is there both ways but the unlock button does not work. Is there a reason why it won’t unlock the gate to the estate? Would appreciate if there’s anything i can do to resolve this issue. Thanking You