internal-mail-in-1.ispapi.net has no MX records.
Question and response
Question
dig internal-mail-in-1.ispapi.net. MX
Answer
The response has no answer records.
Authority
ispapi.net. 3600 SOA ns1011.ispapi.net. support.ispapi.net. 2025040900 86400 7200 3600000 172800
Additional
. 0 OPT ; payload 1400, xrcode 0, version 0, flags 0