sender4-1.zohomail.com has no MX records.
Question and response
Question
dig sender4-1.zohomail.com. MX
Answer
The response has no answer records.
Authority
zohomail.com. 600 SOA ns1.zohocorp.com. dnsadmin.vtitan.com. 2026030301 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0