mailserver.securewebportal.net has no AAAA records.
Question and response
Question
dig mailserver.securewebportal.net. AAAA
Answer
The response has no answer records.
Authority
securewebportal.net. 900 SOA ns1.efscloud.net. efscloud.net.domainsbyproxy.com. 41 600 300 3600000 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0