For one query when explosm.net failed I see:
May 22 07:36:30 damma kresd[17843]: [iterat][00000.00] 'explosm.net.' type 'A' new uid was assigned .01, parent uid .00
May 22 07:36:30 damma kresd[17843]: [cache ][00000.01] => skipping exact RR: rank 030 (min. 030), new TTL -1222
May 22 07:36:30 damma kresd[17843]: [cache ][00000.01] => no NSEC* cached for zone: explosm.net.
May 22 07:36:30 damma kresd[17843]: [cache ][00000.01] => skipping zone: explosm.net., NSEC, hash 0;new TTL -123456789, ret -2
May 22 07:36:30 damma kresd[17843]: [cache ][00000.01] => skipping zone: explosm.net., NSEC, hash 0;new TTL -123456789, ret -2
May 22 07:36:30 damma kresd[17843]: [zoncut][00000.01] found cut: explosm.net. (rank 010 return codes: DS 1, DNSKEY 1)
May 22 07:36:30 damma kresd[17843]: [resolv][00000.01] => NS is provably without DS, going insecure
May 22 07:36:30 damma kresd[17843]: [select][00000.00] NO6: is KO [exploit]
May 22 07:36:30 damma kresd[17843]: [select][00000.01] => id: '36919' choosing: 'andy.ns.cloudflare.com.'@'2a06:98c1:50::ac40:2165#00053' with timeout 10000 ms zone cut: 'explosm.net.'
May 22 07:36:30 damma kresd[17843]: [resolv][00000.01] => id: '36919' querying: 'andy.ns.cloudflare.com.'@'2a06:98c1:50::ac40:2165#00053' zone cut: 'explosm.net.' qname: 'exPlOSM.neT.' qtype: 'A' proto: 'tcp'
May 22 07:36:30 damma kresd[17843]: [worker][00000.01] => connecting to: '2a06:98c1:50::ac40:2165#00053'
May 22 07:36:30 damma kresd[17843]: [select][00000.01] NO6: timed out, but bad already
May 22 07:36:30 damma kresd[17843]: [select][00000.01] => id: '36919' noting selection error: 'andy.ns.cloudflare.com.'@'2a06:98c1:50::ac40:2165#00053' zone cut: 'explosm.net.' error: 3 TCP_CONNECT_FAILED
May 22 07:36:30 damma kresd[17843]: [iterat][00000.01] 'explosm.net.' type 'A' new uid was assigned .02, parent uid .00
May 22 07:36:30 damma kresd[17843]: [select][00000.00] NO6: is KO [exploit]
May 22 07:36:30 damma kresd[17843]: [select][00000.02] => id: '51029' choosing: 'andy.ns.cloudflare.com.'@'2803:f800:50::6ca2:c165#00053' with timeout 10000 ms zone cut: 'explosm.net.'
May 22 07:36:30 damma kresd[17843]: [resolv][00000.02] => id: '51029' querying: 'andy.ns.cloudflare.com.'@'2803:f800:50::6ca2:c165#00053' zone cut: 'explosm.net.' qname: 'ExPLosM.Net.' qtype: 'A' proto: 'udp'
May 22 07:36:35 damma kresd[17843]: [gnutls] (5) REC[0x57135e0]: SSL 3.3 Application Data packet received. Epoch 2, length: 147
…
May 22 07:36:40 damma kresd[17843]: [select][00000.02] => id: '51029' noting selection error: 'andy.ns.cloudflare.com.'@'2803:f800:50::6ca2:c165#00053' zone cut: 'explosm.net.' error: 1 QUERY_TIMEOUT
May 22 07:36:40 damma kresd[17843]: [worker][00000.00] internal timeout for resolving the request has expired
May 22 07:36:40 damma kresd[17843]: [resolv][00000.00] request failed, answering with empty SERVFAIL
I wonder why it looks like it’s trying to run the query over IPv6, I don’t have that available.