Did you run the Z wave repair utility after you added the range extender to your network? Otherwise the devices that were already on the network won’t necessarily use it.
Also, how far is it from the lock?
When people suggest that you add a repeater to assist with a Z wave lock, they are not talking about increasing the range of the network. They are talking about adding a beaming device which can essentially act as an “answering service” for your lock and hold its messages until the lock wakes up again. That’s a different function.
See the community FAQ (the topic title is a clickable link)