Clean the history and start from 0.
sudo service pihole-FTL stop && sudo rm /etc/pihole/pihole-FTL.db && sudo service pihole-FTL start
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When you try to access a url that is blocked by pihole and you whitelist it, and it still doesnt work:
Then apply the blacklist change :
sudo pihole -g 
Then if you try again it will work
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