Sounds like your Gmail is rate limiting the sender.
All those free mail providers such as Google’s Gmail, Microsoft’s Hotmail/Outlook, Yahoo, et al, are doing that, often for various reasons, such as e.g. what they consider to be too many messages in a short time, to something within the email message content that they don’t like, and so forth.
You’re currently pointing your MX record towards a Proxied (
) record.
Therefore, Cloudflare is replacing your “MX” with this:
vlladers.com. 300 IN MX 0 _dc-mx.f5f588f2138b.vlladers.com.
DNS records are generally public information, - if you wish to keep certain data (e.g. IP addresses of Proxied () records private), you can redact them.
However, it makes no sense to redact DNS records related to email traffic, as they will be publicly available anyway.
→
$ dig TXT vlladers.com
vlladers.com. 300 IN TXT "v=spf1 -all"
The TXT (SPF) record here is instructing other mail servers about that your domain name, “vlladers.com”, does NOT send email traffic.
$ dig TXT _dmarc.vlladers.com
_dmarc.vlladers.com. 300 IN TXT "v=DMARC1; p=reject; sp=reject; adkim=s; aspf=s;"
_dmarc.vlladers.com. 300 IN TXT "v=DMARC1; p=none; rua=mailto:[email protected];"
The TXT (DMARC) records here, are conflicting with each other, as you cannot have two of them.
The first one, with the “reject” policy, is instructing other mail servers to refuse email deliveries, that claims to be from your domain name, “vlladers.com”, but where the the email authentication status cannot be validated and connected to your domain name (e.g. DKIM w/Alignment, SPF w/Alignment).
If you’re actually trying to send emails with a “From:” header, that contains an email address under the “vlladers.com” domain name, then the configuration for “vlladers.com” is heavily misconfigured.
In addition, -
The OVH server that you seem to be pointing traffic towards, it is currently having one of these dynamic/generic-looking reverse DNS (PTR) records.
E.g. in the format “ip123.ip-192-0-2.eu”, assuming the example IP address “192.0.2.123”.
Most mail servers out there will refuse deliveries from hosts with such dynamic looking PTR records, or at least, treat your email traffic as suspicious, assuming you’re sending out messages directly from your OVH server (or any other server) with a such “strange” name.
What exactly does that message tell you?
There will be much more information, embedded within that error message.
