smtp2.lhr.netsolir.com has no MX records.
Question and response
Question
dig smtp2.lhr.netsolir.com. MX
Answer
The response has no answer records.
Authority
lhr.netsolir.com. 3600 SOA ns1.netsolir.com. postmaster.netsolir.com. 2007080718 10800 3600 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0