I would try rebooting the Android device and trying again. If that fails, I wonder if your Mac and Android are on the same network.
Sometimes, Wifi routers have split networks, so that there is a guest network and a "normal" network. The guest network can't see the computers on the normal network.
You could try a web browser on the android with the IP address of your Mac and that same port as before. As an example:
192.168.1.100:52199
Your IP address will probably be different.
You could also check the IP address on both the Mac and the Android and compare them. If they aren't in the same range, the router might be isolating them from each other, as I outlined above.
These kinds of issues are sometimes tough to diagnose remotely.
It's quite late here and I'm going to bed. Good luck to you!
Brian.