ab977e1a73fc8f7dc.dualstack.awsglobalaccelerator.com has no CNAME records.
Question and response
Question
dig ab977e1a73fc8f7dc.dualstack.awsglobalaccelerator.com. NS
Answer
The response has no answer records.
Authority
awsglobalaccelerator.com. 386 SOA ns-609.awsdns-12.net. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0