s462.smtp-spf.sureserver.com has no SRV records.
Question and response
Question
dig s462.smtp-spf.sureserver.com. SRV
Answer
The response has no answer records.
Authority
s462.smtp-spf.sureserver.com. 2560 SOA ns1.s462.sureserver.com. hostmaster.s462.smtp-spf.sureserver.com. 1772901734 16384 2048 1048576 2560
Additional
The response has no additional records.