So you restarted your router/dhcpd server or for some other reason you wonder why DHCP is not working on any of your clients? You go and check that named is in fact running fine.
But then you check /var/log/messages and see this error for everything hostname:
named: error (broken trust chain) resolving 'min-api.cryptocompare.com/A/IN': 18.104.22.168#53
I've only ever seen this when the time on the server was off. It is important to make sure you are running ntpd or ntpdate on boot and at all times. Once you change your time to the correct time things will work again.