proxy11.mail.provider.nl has no MX records.
Question and response
Question
dig proxy11.mail.provider.nl. MX
Answer
The response has no answer records.
Authority
provider.nl. 86400 SOA dns.resolver.domains. hostmaster.provider.nl. 2025112701 86400 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0