mail.1pcom.com has no CNAME records.
Question and response
Question
dig mail.1pcom.com. NS
Answer
The response has no answer records.
Authority
1pcom.com. 3428 SOA ns.endstream.net. hostmaster.endstream.net.1pcom.com. 2025071802 14400 900 900 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0