How to contact Seznam.cz postmasters and improve email deliverability?
Matthew Whittaker
Co-founder & CTO, Suped
Published 30 Jul 2025
Updated 14 Aug 2025
5 min read
Summary
Contacting specific internet service providers (ISPs) like Seznam.cz for email deliverability issues can be challenging, as their dedicated postmaster information is not always readily available or easy to navigate. Senders often encounter issues such as bounced emails or blocklisting, which necessitate direct communication with the ISP to understand and resolve the underlying problems. While a generic postmaster@ address is a common starting point, more specific details or alternative contact methods are often sought to expedite troubleshooting and improve inbox placement.
Key findings
Direct contact: Sending an email to postmaster@seznam.cz is often the most effective initial approach, despite its generic nature.
Policy changes: Seznam.cz has tightened its anti-spam policies, requiring valid DKIM signatures for mass emails since April 2015. This is a crucial authentication step to ensure deliverability, as highlighted by their own blog.
Header requirements: Some Czech providers, including potentially Seznam.cz, may require the Precedence: bulk header for promotional or bulk emails, bouncing messages that lack it.
Bounce messages: The content of bounce messages is critical for diagnosing specific delivery issues, providing valuable feedback on why emails are being rejected.
Key considerations
Analyze bounces: Before attempting to contact Seznam.cz, thoroughly review bounce messages for clues regarding the delivery failure. This helps pinpoint the exact issue, whether it is a content filter, sender reputation, or authentication problem.
Authentication: Ensure your email authentication protocols (SPF, DKIM, and DMARC) are correctly configured and aligned. A valid DKIM signature is particularly important for Seznam.cz.
ISP policies: Be aware that ISPs, especially in specific regions, may have unique sending rules. Investigating these (e.g., via their helpdesk or postmaster pages) can prevent unexpected blocks.
Contact strategy: While a generic postmaster@ address is the standard first step, be prepared to provide detailed information about your sending practices. For a broader perspective on contacting mailbox providers, consult relevant guides.
What email marketers say
Email marketers frequently face the challenge of troubleshooting email deliverability issues, especially when dealing with smaller or regional ISPs like Seznam.cz. Their experience often highlights the practical approaches to resolving bounce issues and navigating the sometimes opaque contact channels of mailbox providers. Marketers typically rely on a combination of direct outreach, community insights, and careful analysis of delivery failure messages.
Key opinions
Direct approach: Many marketers find success by directly emailing postmaster@seznam.cz as a first step, even if other contact details are unclear.
Bounce feedback: The bounce message itself is often the most valuable piece of information, guiding them towards the specific cause of the delivery problem, such as being placed on a blacklist or blocklist.
Header importance: Some marketers have noted that Seznam.cz's filters may struggle to categorize emails, making the Precedence: bulk header unexpectedly helpful.
Community insights: Seeking advice from online communities, like Email Geeks, can provide practical tips and alternative contact methods (e.g., helpdesk@firma.seznam.cz) that are not publicly advertised.
Key considerations
Full diagnostic: Before contacting an ISP, gather all relevant information, including the exact bounce message, sending volume, and any recent changes to your sending infrastructure. This helps in a faster resolution.
Postmaster tools: Utilize available postmaster tools, such as the Seznam.cz feedback loop (FBL), to monitor sender reputation and address complaints proactively. For more on deliverability metrics, see our guide.
Community engagement: Participate in email marketing forums and communities to stay informed about specific ISP quirks and to gather collective knowledge on troubleshooting.
Persistence: Resolving deliverability issues with some ISPs can take time and multiple attempts. Be prepared for a sustained effort.
Marketer view
Marketer from Email Geeks suggests that reaching Seznam.cz postmasters can be difficult due to a lack of useful information on their website. The direct approach is often the last resort, hoping someone has more concrete information or a less generic contact method.
29 Jul 2019 - Email Geeks
Marketer view
Marketer from TrulyinboxBlog emphasizes the importance of authenticating your email account as a key step in improving email deliverability. This includes ensuring SPF, DKIM, and DMARC records are properly configured to prevent emails from being flagged as spam.
15 Apr 2025 - TrulyinboxBlog
What the experts say
Email deliverability experts highlight the systematic approach required to troubleshoot and resolve issues with specific ISPs, including Seznam.cz. Their insights often extend beyond simple contact methods, delving into technical configurations, industry standards, and the importance of proactive monitoring. They emphasize that while direct communication is essential, a deeper understanding of bounce messages and authentication protocols is paramount for sustained deliverability.
Key opinions
Standard contacts: Experts advise starting with standard postmaster email addresses as the official channel for communication with ISPs.
Industry forums: Participation in industry forums and working groups, such as IETF DMARC lists or MAAWG, can provide indirect access and insights from ISP representatives, including those from Seznam.cz.
Technical diagnostics: A thorough analysis of bounce messages is crucial, as they contain specific error codes and descriptions that directly inform the troubleshooting process.
Authentication compliance: Experts stress the importance of robust email authentication (SPF, DKIM, DMARC) as a foundational element for good deliverability, especially with ISPs that have tightened their anti-spam policies.
Key considerations
Proactive measures: Beyond reactive troubleshooting, implementing best practices for sender reputation and list hygiene can prevent future issues. Consider checking your blocklist status regularly.
Localized policies: Be mindful that regional ISPs like Seznam.cz may have specific policies that differ from global mailbox providers, requiring tailored sending strategies. For more insights into how to boost deliverability rates, review expert technical solutions.
Feedback loop utilization: Register for and monitor any available feedback loops provided by the ISP to receive complaints and manage subscriber engagement effectively.
Escalation paths: If direct email communication is unsuccessful, consider if there are industry conferences (e.g., Deliverability Summit in Prague, as mentioned by EIN Presswire) or specific individuals (like David Finger at Seznam.cz) who might be reachable.
Expert view
Expert Steve589 from Email Geeks suggests that reaching out to ISPs through standard postmaster addresses is the primary method. While the initial response might be automated, it formally logs the issue and initiates a communication channel.
29 Jul 2019 - Email Geeks
Expert view
Expert from Spamresource.com advises that consistent monitoring of sender reputation is vital for long-term email deliverability. Proactive identification of issues prevents major disruptions in email flow to various ISPs.
10 Jan 2024 - Spamresource.com
What the documentation says
Official documentation from Internet Service Providers (ISPs) like Seznam.cz, or related industry bodies, provides the definitive guidelines for email sending and deliverability. While specific postmaster contact information might not always be prominently displayed, the documentation often details technical requirements, policies regarding bulk sending, and methods for addressing deliverability concerns. Adhering to these documented rules is crucial for ensuring optimal email delivery.
Key findings
Mandatory DKIM: Seznam.cz has explicitly stated that all mass emails must contain a valid DKIM signature to avoid being blocked, a policy implemented since April 2015.
Bulk sending rules: Some Czech providers, like Economia.cz (which runs Freemail), publish specific rules for bulk emailers, including preferred sending times (e.g., 22:00 - 05:00 UTC) and connection limits. This is detailed in their support documentation.
Precedence header: Certain Czech providers may require the Precedence: bulk header for bulk emails to be accepted.
Message size and rate limits: Explicit limits on maximum message size (e.g., 120 KB) and message-per-minute rates (e.g., 300 messages per minute) are sometimes stipulated.
Key considerations
Review FBL services: Check if the ISP offers a feedback loop (FBL) service (e.g., fbl.seznam.cz) to monitor subscriber complaints and proactively manage your sender reputation. This is vital for maintaining a good sender score and avoiding blocklisting.
Adherence to standards: Ensure full compliance with documented technical standards, including required headers and email authentication protocols. This can significantly improve inbox placement and reduce instances of being placed on a blocklist.
Optimal sending: Adjust your sending practices to align with any specified limits or preferred sending times to avoid throttling or rejection. This includes managing parallel connections and overall message volume.
Regular updates: Periodically check the ISP's official news or blog for updates to their anti-spam policies, as these can change and impact your deliverability without prior direct notification. Regularly checking postmaster tools can also provide valuable insights.
Technical article
Official documentation from Blog Seznam.cz states that the Seznam.cz Email service tightened its anti-spam policy from April 1st, 2015. All mass emails that do not contain a valid digital DKIM signature will now be rejected, emphasizing the critical role of email authentication.
03 Mar 2015 - Blog Seznam.cz
Technical article
Documentation from Freemail Economia.cz outlines rules for sending bulk email messages. It prefers off-peak sending, specifically from 22:00 to 05:00 UTC, to ensure smooth message receipt and minimize server load during peak hours.
