- Plesk for Linux
- Plesk for Windows
Outgoing emails sent from Plesk server to mail services like GMail, Yahoo goes to spam folder. How to troubleshoot?
Here is the list of most common reasons why it happens:
- SPF/DKIM/DMARC are not configured on the sender's side;
- Server's IP address is compromised and added to DNS BL;
- Message content does not match requirements for non-spam email. For example, empty message will be marked as spam;
- If sender's mail account is used for sending notifications and most of the users mark this messages as spam, there is a high probability that it will go to Spam folder for other users as GMail has learning algorithms;
How to troubleshoot
1. Use online checkers, like MXToolbox, www.mail-tester.com to verify that email-validation systems are configured for the domain: SPF, DMARC, DKIM.
If some warnings are detected, verify that everything is configured properly and configure if necessary:
Check that TXT record regarding SPF validation present in domain's Home > Domains > example.com > DNS Settings:
Check the How to create SPF rule for the domain? for the details.
Check that TXT record regarding DMARC validation present in domain's Home > Domains > example.com > DNS Settings:
This policy recommends that the receiving mail server does not delete messages even if they fail to check. You can specify a stricter policy. However, note that the receiving server is free to apply its own policy to incoming mail.
Check an overview how DMARC works on this page
Note: On default Plesk installation SPF and DMARC records are added to the domain's DNS Settings during its creation in accordance with DNS Templates
Check that DKIM support is enabled server-wide in Home > Tools & Settings > Server-Wide Mail Settings :
Check that DKIM support is enabled for the domain in Home > Domains > example.com > Mail Settings :
and verify that necessary records are added to domain's DNS Settings:
Note: If external DNS server is being used for the domain, make sure that all the TXT records related to DKIM, DMARC (default._domainkey.<example.com>, _domainkey.<example.com>, _dmarc.<example.com>) from domain's DNS Settings are transferred to external DNS as is.
2. Check that domain's IP is not blacklisted - Email Blacklist Check
3. 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:
cancel at any time
check or money order
for only ($)
free or toll-free
this is not spam
- Suspicious subject of the message, like "How to become a billionaire in 1 month"
If any means server IP was blacklisted, please contact Yahoo, Hotmail or Gmail directly or with your Internet service provider:
- Outlook/Hotmail: Common Microsoft services troubleshooting or contact form
- GMail: Delivery problem form between your domain and Gmail
- Yahoo! Bulk Sender Form - Even if you are not a bulk sender, you will need to complete the form