Having issues with receiveing, no problems sending

Somehow, I am unable to receive emails. Sending out is not an issue. The only clue gathered so far is "TLS doesn’t allow underscore in a domain name. It does show somehow that the CF adds in an “underscore” on my MX.

Anyone has any clue how to resolve this?


Could you share a censored screenshot of your DNS section in Cloudflare Dashboard?
IPs and rootdomain can be censored, but please no subdomain-names and proxy-status.

@M4rt1n ,
This isn’t in the DNS records but pointed out from intodns report under the following
|Error|MX name validity|The MX records that do not seem valid hostname:

Also, in my exim4 it shows “2021-05-21 03:25:32 TLS error on connection from mail-pg1-f202.google.com [] (gnutls_handshake): A disallowed SNI server name has been received.”


This is what you asked for?


Please turn off Proxy (:orange:) and change to DNS Only (:grey:) these subdomains:

  1. ftp
  2. imap
  3. mail
  4. pop
  5. smtp

…actually everything but “webmail”, “www” & rootdomain itself

Then try again :slight_smile:

1 Like

Another problem here is:

  1. SMTP Banner Check
  2. SMTP Reverse DNS Mismatch

The Mailserver of your .com Domain actually matches your domain-name, but with the .sg ending.
So you probably have your Mailserver not configurated properly.

Precisely, cloudflare nameservers keep on reporting this errant MX nameserver with an underscore even though you can see in my earlier screenshot that my MX does not have an underscore at all.

Somehow cloudflare is pulling this record or insisting that that is the dns record when nowhere on my VPS reflects this underscore name.

I have tried to purge everything from the cache many times but it still does not work.

I really am at my wits end…


Cloudflare does NOT proxy/handle or answer any Mail related thing. SMTP Banner Check is not getting done on DNS level. Its your server (the one the MX Entry points to) that reports this.

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