mail.ph.rlb.com has no MX records.
Question and response
Question
dig mail.ph.rlb.com. MX
Answer
The response has no answer records.
Authority
rlb.com. 21600 SOA ns1.netnames.net. hostmaster.cscdns.net. 2018080617 10800 1800 3600000 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0