mail.thomasville.org has no CNAME records.
Question and response
Question
dig mail.thomasville.org. NS
Answer
The response has no answer records.
Authority
thomasville.org. 300 SOA dns1.thomasville.org. na.thomasville.org. 2006072812 28800 14400 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0