Unblockr does not support DNS over TLS at moment.
If you wish to use the private dns option then please use a ddns as in no-ip (guide on help page)
However you can install the android Unblockr DNS app. This is available from amazon playstore or
Once installed you can either run the app from your menu or go to your settings and select vpn instead of private dns (make sure this is set to off) and the app will be within VPN options. Run it and add your api key and select your nearest server... in settings highlight the start on boot option.
Your Unblockr will now be on your device whether you are on your network or mobile without having to do anything.