BTT Remote doesn’t see my Mac on the network

I have a MacBook Pro running MacOS 10.13.6 and BTT 2.645, and I just installed BTT Remote on my iPhone. When I launch the BTT Remote app, it shows another Mac on the network, but it does not show my computer.

I have tried disabling the firewall on my Mac, but it still doesn’t show up in the mobile app. What do I need to configure on my computer so that BTT Remote sees it?