mx0a-00100303.pphosted.com has no SRV records.
Question and response
Question
dig mx0a-00100303.pphosted.com. SRV
Answer
The response has no answer records.
Authority
pphosted.com. 300 SOA ns1.proofpoint.com. ops.proofpoint.com. 2026065990 1200 120 2419200 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0