spfmessagelabs.skillsoft.com has no AAAA records.
Question and response
Question
dig spfmessagelabs.skillsoft.com. AAAA
Answer
The response has no answer records.
Authority
skillsoft.com. 86400 SOA udns1.cscdns.net. hostmaster.cscdns.net. 7466 86400 86400 86400 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0