digitalocean.pc2linux.com has no MX records.
Question and response
Question
dig digitalocean.pc2linux.com. MX
Answer
The response has no answer records.
Authority
pc2linux.com. 300 SOA dns0.zoneedit.com. zone.zoneedit.com. 1760033925 2400 360 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0