_spf.spamgateway.comodo.com has no AAAA records.
Question and response
Question
dig _spf.spamgateway.comodo.com. AAAA
Answer
The response has no answer records.
Authority
comodo.com. 2560 SOA ns1.nurd.com. dnsadmin.nurd.com. 172800 60 60 60 60
Additional
The response has no additional records.