web.yas-online.net has no MX records.
Question and response
Question
dig web.yas-online.net. MX
Answer
The response has no answer records.
Authority
web.yas-online.net. 600 SOA ch.ch-inter.net. admin.neic0.de. 2019112103 10800 3600 604800 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0