Emails sent from a Plesk server to mail services like Gmail, Outlook or Yahoo! Mail appear in spam. How to troubleshoot?

Updated November 13, 2019 08:56

Applicable to:

Plesk for Linux
Plesk for Windows

Question

Outgoing emails sent from a Plesk server to mail services like Gmail, Yahoo, Outlook go to the spam folder. How to troubleshoot?

Answer

Note: This guide is intended for Plesk administrators. If you are a domain owner, please contact your service provider for assistance.

Here is the list of the most common reasons why it may happen:

SPF/DKIM/DMARC features are not configured in Plesk.
An email content matches spam description. For example, an empty email message will be marked as spam.
Server IP address is blacklisted.
If a sender's email account is used for sending email notifications and other users mark these messages as spam, there is a high probability that these emails will go to the spam folder for other users as Gmail has learning algorithms;
Server PTR record is not corect.

How to troubleshoot

Use online checkers, like MXToolBox and www.mail-tester.com, to verify that email validation features are configured for the domain: SPF, DMARC, DKIM.

If some warnings are detected, verify that everything is configured properly:
- SPF
  
  Make sure there is a TXT SPF record in domain's DNS settings at Domains > example.com > DNS Settings:
  
  Note: By default, a SPF record is added to the domain's DNS zone during a domain creation in accordance with the Plesk DNS Template.
  
  To learn more about SPF, visit this KB article.
- DMARC
  
  Make sure there is a TXT DMARC record in domain's DNS settings at Domains > example.com > DNS Settings::
  
  Note: By default, a DMARC record is added to the domain's DNS zone during a domain creation in accordance with the Plesk DNS Template.
  
  To learn more about DMARC, visit its overview page.
- DKIM
  
  Make sure that DKIM support is enabled server-wide in Plesk at Tools & Settings > Mail Server Settings:
  
  Make sure that DKIM support is enabled for a domain in at Domains > example.com > Mail Settings:
  
  Finally, verify that necessary records are present in domain's DNS settings:
  
  To learn more about DKIM, SPF, and DMARC Protection, visit this Plesk documentation page.
  
  Note: In case of multiple DKIM keys are configured, verify that they are set on different selectors (default._domainkey.example.com, new._domainkey.example.com, etc.)
  
  If an external DNS server is used for a domain, make sure that all TXT records related to DKIM and DMARC (default._domainkey.<example.com>, _domainkey.<example.com>, _dmarc.<example.com>) from domain's DNS settings are transferred to external DNS as is.
Validate content of the message that was marked as spam. Common message attributes that can trigger spam filters:
- The body of the message is empty or contains spam trigger words like:
  
  PLESK_INFO: amazing, cancel at any time, check or money order, click here, congratulations, dear friend, for only ($), free or toll-free, great offer, guarantee, increase sales, order now, promise you, risk free, special promotion, this is not spam, winner
- Suspicious subject of the message, like "How to become a billionaire in 1 month"
Once done with the steps above, try to send a test email to a mail service like Gmail, Outlook, Yahoo! Mail, etc. If this email still hits the Spam folder there, contact support of a mail service to remove your IP address from their blacklists:

IP address of a Plesk mail server got blacklisted. How to troubleshoot?

Comments

11 comments

Soufiane Abid May 08, 2019 22:53

Hi

All settings is good but when check email source

SPF "pass"

dkim "pass"

dmarc "pass"

but message go to spam folder !!

any idea or solve for this problem

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Daria Gavrilova May 09, 2019 03:04
Hello @Soufiane Abid,

As all settings are correct, but emails still hit the Spam folder, please contact support of a corresponding mail service to remove your IP address from their blacklists:
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Michel Renard June 12, 2019 21:23

Hello @Daria

I know the answer, because I have already had this kind of problem with other panels. Even Microsoft do not know given correct answer because I joined @Soufiane, I have the same thing is one for an anomaly, this falls in junk mail.

Michel Renard

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Ivan Postnikov June 13, 2019 13:16

Hello @Michel Renard,

Thank you for sharing your user experience.

Indeed, as Daria said, if the message passes SPF, DKIM and DMARC checks and the server is not blacklisted but mail still arrived to the junk folder then the issue is on the mail provider side.

I would recommend you to review mail headers of the "junk" messages and sent them to mail provider technical support to investigate the reasons why it happened.

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Michel Renard June 13, 2019 20:06

Hello

They just answered me and told me about JMRP and mail formatting, I use Outlook, the HTML format would be a big risk factor regarding the message sending?

Are your lines, SPF and DMARC the right ones for sending a message?

Michel

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Michel Renard June 17, 2019 17:44

Hello

For my part is via the configuration it works great.

I had to sign the agreement as Microsoft 'JMRP'.

there is

Michel Renard (FoxStudio)

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Le Nguyen Kha June 26, 2019 04:13

Dear Kuzma Ivanov

My hosting running Plesk version 12.5.30 and my boss dont want to upgrade it, so i can not use DKIM system. Because of that, our emails send from my hosting sever always go into spam inbox. Could you tell me can i fix that issue without upgrade Plesk version, or if i upgrade to lastest version and enable DKIM how many percent our emails will go to our customer's inbox?

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Daria Gavrilova July 01, 2019 08:41
Hello @Michel Renard,

Thank you for the update.

Let me address your questions one by one:
> the HTML format would be a big risk factor regarding the message sending?
No, there should be no risks in regards of it.

> Are your lines, SPF and DMARC the right ones for sending a message?
Yes, SPF and DMARC are the correct ones if it is setup properly.
More information about SPF and DMARC configuration you may find here:
- What is SPF? How to configure and use SPF on a Plesk server?
- How to enable DMARC in Plesk
> For my part is via the configuration it works great. I had to sign the agreement as Microsoft 'JMRP'.

Glad to hear that everything works as expected now.
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Daria Gavrilova July 01, 2019 08:49
Hello @Le Nguyen Kha,

Thank you for your question.

Until Plesk is not upgraded to the newer version, there is no way to use DKIM.
So it is highly recommended to upgrade Plesk to the newer version using the following guide: How to upgrade Plesk to the next release

> how many percent our emails will go to our customer's inbox?
There is no statistics on this matter, however to ensure that everything is setup correctly and your IP address is not in the blacklists, please use the services like MXToolbox blacklist checker or Blacklist Check provided by WhatIsMyIPAddress.com.

If everything is setup properly, your IP is not blacklisted, however emails still hit the Spam folder, contact support of a mail service to remove your IP address from their blacklists:
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Michele Iannello November 02, 2019 05:29

Hello,

I have setup Plesk Control Panel at a custom url (ps.mydomain.com) using the "Custom Plesk Hostname" extension.

Where do I find the dkim _domainkey.ps.mydomain.com to use in mydomain.com DNS to validate the email source?

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Anton Maslov November 08, 2019 00:29

Hello, mydomain.com will have dkim like _domainkey.mydomain.com. DKIM is based on domain name, not Plesk URL. If DKIM is enabled you will see it under Website & Domains > domain.com > DNS settings.

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