mail2550.paypal-notification.com has no CNAME records.
Question and response
Question
dig mail2550.paypal-notification.com. NS
Answer
The response has no answer records.
Authority
paypal-notification.com. 300 SOA ppdns.paypal.com. hostmaster.paypal.com. 301 7200 600 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0