Emails blocked

[Sergey Petrenko]

Hello,

the emails that we are sending to .messagelabs.com being blocked with the following messages :

<-- 553-DMARC domain authentication fail. Refer to the
<-- 553-Troubleshooting page at https://knowledge.broadcom.com/e
<-- 553-xternal/article?legacyId=TECH246726 for more
<-- 553 information. (#5.7.1)

Sometimes emails received, sometimes not. It's not a permanent error.

Emails have good DKIM sign and verified DMARC record. Others email providers accept that emails without errors. 

Kindly help to resolve.

[Aiaga Toleafoa]

My client is complaining of fail to their overseas partner> i checked our Mdaemon log as per error below. Please why I received error below. Please advise

thanks



*  Connection established 123.176.73.72:65169 --> 54.83.87.114:25

  Waiting for protocol to start...

  <-- 220 mail555.messagelabs.com ESMTP Wed, 19 Jan 2022 00:49:11 +0000

  --> EHLO angel.samoa.net.ws

  <-- 250-mail555.messagelabs.com Hello angel.samoa.net.ws [100.112.12.210]

  <-- 250-SIZE 52428800

  <-- 250-8BITMIME

  <-- 250-PIPELINING

  <-- 250-PIPE_CONNECT

  <-- 250-CHUNKING

  <-- 250-STARTTLS

  <-- 250-PRDR

  <-- 250 HELP

  --> STARTTLS

  <-- 220 TLS go ahead

  SSL negotiation successful (TLS 1.2, 256 bit key exchange, 256 bit AES encryption)

  SSL certificate is valid (matches cluster1a.us.messagelabs.com and is signed by recognized CA)

  --> EHLO angel.samoa.net.ws

  <-- 250-mail555.messagelabs.com Hello angel.samoa.net.ws [100.112.12.210]

  <-- 250-SIZE 52428800

  <-- 250-8BITMIME

  <-- 250-PIPELINING

  <-- 250-PIPE_CONNECT

  <-- 250-CHUNKING

  <-- 250-PRDR

  <-- 250 HELP

  --> MAIL From:<[e-mail]> SIZE=3558

  <-- 250 OK

  --> RCPT To:<[e-mail]>

  <-- 421 Service Temporarily Unavailable

  --> QUIT

[Paul Fletcher]

It looks like your server is not correctly selecting the target MX record to send to, in accordance with RFC 5321.

[Paul Fletcher]

Please check the DNS configuration for the target domain - i.e. who the email is actually addressed to, using a tool such as viewdns.info.  These kind of intermittent problems can occur when some of the DNS servers for the domain are incorrectly configured or are unreachable.