Sometimes, especially after updates/reboots you will see alerts like
this:
....
18:46:55 < zodbot> PROBLEM - unbound-tummy01.fedoraproject.org/Unbound 443/tcp is WARNING: DNS WARNING - 0.037 seconds response time (dig returned an error status) (noc01)
18:51:06 < zodbot> PROBLEM - unbound-tummy01.fedoraproject.org/Unbound 80/tcp is WARNING: DNS WARNING - 0.035 seconds response time (dig returned an error status) (noc01)
....
To correct this, restart unbound on the relevant node (in the example