Intercom with door lock release.

[JORA]

Hello  i have recently installed a Bell 900 series intercom with door latch release, every seems to work ok the buzzer outside the the telephone inside and there is a button on handset that when pressed releases the door lock to let a person in, the only thing not working lock release it buzzes but does not open to release the lock any ideas thank you.  

https://www.electriclock.net/product/bell-systems-900-series-audio-door-entry-systems/