Apex domains cannot have CNAME records.
Question and response
Question
dig gsm1900.org. NS
Answer
gsm1900.org. 5 NS a14-65.akam.net.
gsm1900.org. 5 NS a13-67.akam.net.
gsm1900.org. 5 NS a6-66.akam.net.
gsm1900.org. 5 NS a8-66.akam.net.
gsm1900.org. 5 NS a1-167.akam.net.
gsm1900.org. 5 NS a7-65.akam.net.
Authority
The response has no authority records.
Additional
a6-66.akam.net. 4 A 23.211.133.66
a7-65.akam.net. 4 A 23.61.199.65
a8-66.akam.net. 4 A 2.16.40.66
a1-167.akam.net. 4 A 193.108.91.167
a13-67.akam.net. 4 A 2.22.230.67
a14-65.akam.net. 4 A 184.26.161.65
a6-66.akam.net. 4 AAAA 2600:1401:1:0:0:0:0:42
a7-65.akam.net. 4 AAAA 2600:1406:32:0:0:0:0:41
a8-66.akam.net. 4 AAAA 2600:1403:a:0:0:0:0:42
a1-167.akam.net. 4 AAAA 2600:1401:2:0:0:0:0:a7
a13-67.akam.net. 4 AAAA 2600:1480:800:0:0:0:0:43
a14-65.akam.net. 4 AAAA 2600:1480:1800:0:0:0:0:41
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0