mail2.connect.spb.ru has no CNAME records.
Question and response
Question
dig mail2.connect.spb.ru. NS
Answer
The response has no answer records.
Authority
connect.spb.ru. 184 SOA ns2.connect.spb.ru. admin.connect.spb.ru. 9 3600 900 3600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0