lettersback.twodollarsmail.com has no NS records.
NS records for this zone are defined at twodollarsmail.com.
NS records for this zone are defined at twodollarsmail.com.
Question and response
Question
dig lettersback.twodollarsmail.com. NS
Answer
The response has no answer records.
Authority
twodollarsmail.com. 3601 SOA dns1.registrar-servers.com. hostmaster.registrar-servers.com. 1773061171 43200 3600 604800 3601
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0