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[RESOLVED] Error: "550-5.7.1 This message does not have authentication information or fails to pass"

550-5.7.1 This message does not have authentication information or fails to pass


When the user sends the messages to external mail servers, messages are not delivered or sent to the spam folders.

A bounce-back message may occur in Plesk for Windows in MailEnable logs

%plesk_dir%\Mail Servers\Mail Enable\Logging:

MailEnable: Message could not be delivered to some recipients.
The following recipient(s) could not be reached:
Recipient: []
Reason: 550-5.7.1 [2a04:2180:0:2::77] Our system has detected that this message does not
Server sends an email about the bounce to the server.

Reporting-MTA: dns;
X-Postfix-Queue-ID: 53E6510D85C
Arrival-Date: Fri, 13 Oct 2017 03:45:16 -0500 (CDT)
Final-Recipient: rfc822;
Action: failed
Status: 5.7.1
Diagnostic-Code: smtp; 550-5.7.1 This message does not have authentication information or fails to pass 550-5.7.1 authentication checks. To best protect our users from spam, the 550-5.7.1 message has been blocked. Please
visit 550-5.7.1 for more 550
5.7.1 information. e99si513617itd.159 – gsmtp
Server do not have the set-up of DKIM and SPF.

Server do not have correct rDNS.

IP address of the server is blacklisted.

  • Because of spamming, IP address may be blacklisted.
  • Domain requirement doesn’t satisfy the requirements of Google.
  • Mail server’s requirement is to have a verified rDNS, DKIM, and SPF must be enabled for delivering messages.
Plesk: Plesk is a web hosting platform available with the control panel through which administrator of the server can setup email accounts, new sites and DNS through the interface that is based on web.

DKIM: DKIM is DomainKeys Identified Mail, a method for detecting forgery of sender address in mails. It is a technique used in email spams. With DKIM receiver can check the email sent from the particular domain actually authorized by the domain’s owner. Administration of the server is allowed easily by setting DNS, email accounts for business and new sites.

SPF: SPF is Sender Policy Framework, a technique for email authentication that is used to prevent the spammers of email from sending messages as a representative of domain. An organization can publish their authorized mail server with SPF.

rDNS: rDNS is Reverse Domain Name System, method used to resolve IP address into domain name, Similar to Domain Name system as it resolves domain names into related IP address.


Setting perfect rDNS

Removing the IP address of the server from blacklist
  1. Navigating to the spam list of the server.
  2. Following the procedures for delisting.
Enabling DKIM and SPF.
  1. Select Mail Server Settings from Tools & Settings.
  2. Set DKIM Spam Protection and Enable SPF Spam Protection to Check Incoming Mail for activation.
When the IP address of the Plesk is blacklisted, follow the below steps.
  1. Log in Plesk.
  2. Change the outgoing mail’s IP address.
  3. Enable the Outbound Spam and search the spam’s source.
  4. IP address should be unblocked.
  5. When the IP address of the Plesk is available in blacklist of Gmail, contact the mail support of Google to remove the IP address of the server from Google.
When the IP of the Plesk is not blacklisted, you have to configure the mail settings for the domain,
  1. SPF may be missing or misconfigured in MXtoolbox Report, you can set up as per the error: Mail from Plesk server is rejected with error: 550-5.7.1 is likely unsolicited mail. Now you need to check the SPF for the domain.
  2. If records of rDNS in MXtoolbox Report are misconfigured, you have to contact the IP address provider or domain registrar for creating rDNS record.
  3. Check if each the requirements of the Google mail are met.
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