app5.syncedtool.com has no MX records.
Question and response
Question
dig app5.syncedtool.com. MX
Answer
The response has no answer records.
Authority
syncedtool.com. 86400 SOA ns1.efscloud.net. root.efscloud.net. 56 86400 7200 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0