Why don't you upgraded to 19.07.1? ;- ) Seriously, had also some problems during migration with unbound / dnsmasq. You should enable verbose logging and take a look.
The adblock running 19.07.0 has a different configuration file layout, so if you try to start adblock running 19.07.0 with a config von 18.06.X - this does not work.
Replace the /etc/config/adblock whith the original one from adbock (from the 19.07.0 repo), restart and edit the configuration as you like ...