Dig status: NXDOMAIN. How to fix?

Question

linux

I am trying to set up a mail server on a VDS. OS Ubuntu 18.04 LTS. I use this guide. The first problem I encountered was MX records:

# Find the MX (mail exchange) server
$ dig MX idice.ml +short
10 mail.idice.ml.

# Find the ip address of the mx server
$ dig mail.idice.ml +short

The last command did not produce anything and I decided to do this:
$ dig mail.idice.ml
In response, I get this:

; <<>> DiG 9.11.3-1ubuntu1.3-Ubuntu <<>> mail.idice.ml
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 40045
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;mail.idice.ml.                 IN      A

;; AUTHORITY SECTION:
idice.ml.               1799    IN      SOA     win-s1ruvds-dns.ruvds.com. hostmaster.ruvds.com. 7 900 600 86400 3600

;; Query time: 68 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Fri Feb 08 19:19:27 MSK 2019
;; MSG SIZE  rcvd: 114

As far as I understood, status: NXDOMAIN means "Non-Existent Domain" (non-existent domain). Apparently, mail will not work for me if this is left like this ...
I registered the domain on freenom.com. I registered the ruvds dns there, on which I ordered the vds, and in the ruvds panel I registered the MX-record:

Did I do everything right, and if so, how to fix the status: NXDOMAIN?

Answer 1

Add an A record for the mail.idice.ml domain specifying the server address