mail229252.rsac1.com has no CNAME records.
Question and response
Question
dig mail229252.rsac1.com. NS
Answer
The response has no answer records.
Authority
rsac1.com. 2479 SOA win-7lbvsc0nb6b. hostmaster. 26 900 600 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0