@jac Typically you want your domain’s MX records to point to FQDN server name, e.g. foo.example.eg
% drill stockportcounty.fans mx
;; ->>HEADER<<- opcode: QUERY, rcode: NOERROR, id: 63911
;; flags: qr rd ra ; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;; stockportcounty.fans. IN MX
;; ANSWER SECTION:
stockportcounty.fans. 600 IN MX 10 stockportcounty.fans.
Yours do not. Although a bit more drillin’ and reverse lookup indicates thusly;
% drill stockportcounty.fans
;; ->>HEADER<<- opcode: QUERY, rcode: NOERROR, id: 160
;; flags: qr rd ra ; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;; stockportcounty.fans. IN A
;; ANSWER SECTION:
stockportcounty.fans. 600 IN A 65.108.63.35
;; AUTHORITY SECTION:
;; ADDITIONAL SECTION:
;; Query time: 127 msec
;; SERVER: 204.8.232.207
;; WHEN: Sun Oct 10 19:37:02 2021
;; MSG SIZE rcvd: 54
<kvg@loon:~>% drill -x 65.108.63.35
;; ->>HEADER<<- opcode: QUERY, rcode: NOERROR, id: 57802
;; flags: qr rd ra ; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;; 35.63.108.65.in-addr.arpa. IN PTR
;; ANSWER SECTION:
35.63.108.65.in-addr.arpa. 86400 IN PTR vps.stockportcounty.fans.
I think you probably want your mx record to point to vps.stockportcountry.fans.
It is important for forward and reverse lookups for MX records jive. Maybe you are looking like a spammer in that they do not?
Edit: But at least you have a reverse record, many spammers do not, so that is a big red flag.