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Expected Behaviour:
-hardware: Raspberry Pi Model B 2012
-OS: Raspian 10 (Buster)
-Pi-Hole: v5.18.4
-FTL: v5.25.2
-Web interface: v5.21
Today, I attempted to run pihole -up and received the message that Buster was no longer supported, so I ran
sudo PIHOLE_SKIP_OS_CHECK=true pihole -r
I chose the repair option, and the install appeared to be successful.
I would expect Pi-Hole to continue running as before.
Actual Behaviour:
I am now getting SERVFAILs on random domains.
A workaround I found is when I change my upstream DNS server to for example Quad9, DNS resolution starts working again. Previously, my upstream DNS server was a DNS server provided behind the VPN I pay for along with its public IP as a backup.
When I try to change DNS settings from the web interface, I now get the message
There was a problem applying your settings.
Debugging information:
PHP error (2): fsockopen(): unable to connect to 127.0.0.1:4711 (Connection refused) in /var/www/html/admin/scripts/pi-hole/php/FTL.php:47
and FTL stops for about 10-15 seconds before restarting. Not sure if this is related.