"Because it's a phone app I can not use a DNS sniffer."
But you can investigate your blocked domains stats to find the related domain names:
https://dashboard.opendns.com/stats/all/blockeddomains
Google use so many domains, different from google.com.
Also, you can use a DNS sniffer while installing it on a computer and sending the DNS queries from your smart device through this computer. Programs you need on the computer are: