mail29.world4you.com has no MX records.
Question and response
Question
dig mail29.world4you.com. MX
Answer
The response has no answer records.
Authority
world4you.com. 3600 SOA ns-ionos.ui-dns.com. dnsadmin.ionos.com. 2025042089 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0