so the problem you have here is that you are on a local (192.168..) IP address. this means that Let's Encrypt cannot provide a valid SSL certificate for you.
your options are:
- set up a local certificate authority that secures your development machine, and install that certificate on your android device (hard, time-consuming)
- mess with Central's code to remove HTTPS checks and run everything insecure (not hard, but dangerous)
- reinstall Central using a public domain name as suggested in the documentation, rather than use a local IP address