Summary
Resolving 550 5.7.1 email blocklist errors when sending through platforms like 17hats typically involves a multi-pronged approach focused on identifying the block, requesting removal, and improving sender reputation. A frequent cause highlighted is emails being routed through services with poor reputations, such as eigbox.net, which is associated with large hosting providers like Endurance known for IP rotation rather than addressing root deliverability problems. For users on shared IP addresses, the email service provider, 17hats in this case, is generally responsible for delisting and managing the reputation of their shared IPs. In other scenarios, the issue stems from the sender's own domain or content, necessitating direct action. The most effective resolution steps include scrutinizing bounce messages for specific blocklist details, utilizing blocklist checker tools, proactively requesting delisting, and diligently implementing best practices for email hygiene and authentication.
Key findings
- Eigbox.net Connection: Emails sent via eigbox.net, often linked to Endurance hosting, frequently trigger 550 5.7.1 errors due to a very poor reputation. The problem depends on whether 17hats defaults to eigbox.net or if the user configured it as a smart host.
- Shared IP Responsibility: If you are on a shared IP address provided by 17hats, the email service provider is accountable for resolving blocklist issues with receiving mail servers like Microsoft, as shared IP problems usually stem from other clients.
- Blocklist Identification: A 550 5.7.1 error almost always indicates your sending IP or domain is on a blocklist. Identifying the specific blocklist from the bounce message or using online checker tools is the critical first step.
Key considerations
- Delisting Process: Once a blocklist is identified, visit its website to understand and follow their specific delisting or removal request procedures.
- Contacting 17hats Support: For issues related to shared IPs or 17hats' underlying sending infrastructure, contact their support for assistance with delisting, understanding their IP reputation, or advising on internal sending practices.
- Sender Reputation & Hygiene: Maintain a healthy sender reputation by cleaning your email lists, ensuring all recipients are opted-in, avoiding content that triggers spam filters, and monitoring engagement.
- Email Authentication Setup: Ensure your domain's SPF, DKIM, and DMARC records are correctly configured. While 17hats manages much of the sending infrastructure, proper domain authentication is crucial for proving legitimacy and preventing future blocks.
What email marketers say
11 marketer opinions
When encountering a 550 5.7.1 blocklist error originating from 17hats, the immediate priority is to diagnose the specific blocklist issue. This often involves checking the full bounce message for explicit blocklist names or using online tools to identify if your sending IP or domain is listed. A significant point of concern raised by experts is the routing of emails through services with very poor reputations, such as eigbox.net, which is associated with large hosting companies known for merely rotating problematic IPs. In cases where users are on shared IP addresses managed by 17hats, the responsibility for resolving the block and improving sender reputation falls to 17hats directly. Beyond identification, a comprehensive resolution strategy involves formally requesting delisting from the relevant blocklists, while simultaneously implementing rigorous email hygiene practices and ensuring robust email authentication to prevent re-listing and foster long-term deliverability.
Key opinions
- Undesirable Sending Infrastructure: A frequent underlying cause of 550 5.7.1 errors when sending via 17hats is the use of email sending infrastructure, such as eigbox.net, which belongs to large hosting providers like Endurance known for having a very poor reputation and rotating blocked IPs instead of fixing root issues.
- ESP's Role in Shared IP Blocks: If your 17hats account utilizes shared IP addresses, the platform, as your Email Service Provider, bears the primary responsibility for addressing blocklist entries with receiving mail servers like Microsoft, since these issues often stem from other clients on the same IP.
- Bounce Message Diagnostics: The 550 5.7.1 error itself signifies a blocklist issue, and the most immediate diagnostic step is to carefully review the full bounce message for explicit mentions of the specific blocklist name or a URL, which guides the delisting process.
Key considerations
- Identify and Address Blocklists: Upon receiving a 550 5.7.1 error, use online blocklist checker tools (e.g., MXToolbox) to identify the specific blocklist your domain or sending IP is on, and then follow their prescribed delisting procedures.
- Leverage 17hats Support: For complex issues, particularly those involving shared IPs or 17hats' sending infrastructure, engage their support team who can provide insights into their IP reputation or assist with specific sending practices within the platform.
- Proactive Sender Reputation Management: Sustain a positive sender reputation by consistently maintaining a clean, opted-in email list, monitoring recipient engagement, and avoiding content that triggers spam filters to prevent future blockages and ensure long-term deliverability.
- Verify Email Authentication: Ensure your domain's SPF, DKIM, and DMARC records are accurately configured in your DNS. While 17hats handles much of the sending setup, proper authentication is crucial for recipients to verify email legitimacy and enhance sender trust.
Marketer view
Marketer from Email Geeks explains that if the user is on a shared IP, as suspected for low volume senders, the email service provider (17hats) is responsible for resolving the block with Microsoft. This is because shared IP blocks are typically caused by other clients on the same IP, and 17hats would need to use their internal systems to identify and take corrective actions against those clients.
9 Jul 2024 - Email Geeks
Marketer view
Marketer from Email Geeks states that the email is coming out via eigbox.net, which has a very poor reputation and is likely the source of the problem. He suggests that eigbox.net might be related to iPage or similar hosts, advising the user to move away from them for email. He further explains that the root problem is mail from 17hats being sent via an eigbox host. The solution depends on whether 17hats always uses eigbox to send, or if the user has configured 17hats to use their eigbox webhost as a smart host. If the latter, undoing that configuration could resolve the issue, as eigbox is described as 'vile'.
5 Mar 2025 - Email Geeks
What the experts say
2 expert opinions
To resolve 550 5.7.1 email blocklist errors, which signal a permanent sending failure often due to blocklisting, poor sender reputation, or content violations, the primary focus is on comprehensive self-assessment and corrective measures. This involves systematically checking your sending IP address and domain against public blocklists, meticulously reviewing your email content to eliminate elements that trigger spam filters, and rigorously verifying the correct implementation of email authentication protocols like SPF, DKIM, and DMARC. Addressing these areas is crucial for enhancing your sender reputation and ensuring long-term deliverability, regardless of the sending platform used, including 17hats.
Key opinions
- Blocklist Indication: The 550 5.7.1 error is a strong indicator that your sending IP or domain may be listed on one or more public blocklists.
- Content and Reputation Triggers: Issues with email content that activate spam filters, alongside a low sender reputation, are key factors contributing to delivery failures and the 550 5.7.1 error.
- Authentication's Role: Correctly configured email authentication mechanisms, such as SPF, DKIM, and DMARC, are essential for bolstering sender trustworthiness and avoiding blockages, which directly impact the resolution of 550 5.7.1 errors.
Key considerations
- Perform Blocklist Checks: Systematically check your sending IP address and domain against common public blocklists to identify any current listings causing the 550 5.7.1 error.
- Refine Email Content: Carefully review and modify your email content to eliminate elements known to trigger spam filters, ensuring your messages appear legitimate and avoid rejection.
- Strengthen Email Authentication: Verify that SPF, DKIM, and DMARC records for your sending domain are correctly configured, as robust authentication is vital for establishing sender legitimacy and improving deliverability.
- Cultivate Sender Reputation: Actively manage and improve your sender reputation through consistent adherence to email best practices, as a positive reputation is crucial for avoiding future blocks and ensuring messages reach their intended recipients.
Expert view
Expert from Spam Resource explains that 550 5.7.1 errors, often related to blocklists or spam policy, require senders to check their sending IP and domain against public blocklists. He also advises improving email content to avoid spam triggers and ensuring proper email authentication (SPF, DKIM, DMARC) is in place, as these factors significantly impact sender reputation and deliverability, which are key to resolving such blocks when sending from platforms like 17hats.
22 Sep 2023 - Spam Resource
Expert view
Expert from Word to the Wise explains that a 550 5.7.1 error indicates a permanent failure, often due to being on a blocklist, violating content policies, or having a poor sender reputation. To resolve this when sending from any platform, including 17hats, she recommends checking your sending IP or domain against common blocklists, reviewing your email content for elements that might trigger spam filters, and ensuring your sender reputation is healthy with correct authentication mechanisms like SPF, DKIM, and DMARC implemented.
6 Jul 2024 - Word to the Wise
What the documentation says
4 technical articles
Resolving 550 5.7.1 email blocklist errors, which are often permanent rejections, centers on identifying the specific blocklist, meticulously following their delisting procedures, and improving sender hygiene. Documentation consistently points to the sending IP address or domain being listed, emphasizing the need to review bounce messages for precise blocklist details. Proactive steps, such as refining email content, ensuring proper authentication, and maintaining a strong sender reputation, are crucial for preventing future issues and ensuring deliverability. For persistent problems, especially when using a platform like 17hats, engaging their support for assistance with delisting or understanding specific blocks is also a recommended step.
Key findings
- Blocklist as Core Cause: The 550 5.7.1 error is a clear indication that your sending IP address or domain is likely listed on one or more spam blocklists.
- Bounce Message for Diagnosis: Detailed information within the bounce message is crucial for identifying the specific blocklist that caused the rejection, guiding the delisting process.
- Permanent Rejection Type: This error often signifies a 'hard bounce' or permanent rejection, indicating a severe issue that requires immediate attention rather than just re-sending.
- Sender Practices Impact: Poor sending practices, including email content that triggers spam filters, a low sender reputation, and inadequate email authentication, are common root causes of these blocklist errors.
Key considerations
- Direct Blocklist Delisting: After identifying the specific blocklist, visit its official website to follow their prescribed delisting or removal request procedures.
- Content Review and Refinement: Carefully examine your email content for any spam trigger words or elements that could lead to your messages being flagged, and revise as necessary.
- Email Authentication Verification: Ensure your domain's SPF, DKIM, and DMARC records are accurately set up to verify your sender identity and improve deliverability.
- Proactive Reputation Management: Sustain a positive sender reputation by maintaining a clean, opted-in email list and adhering to best sending practices to prevent future blockages.
- Consult Your ESP: If the issue persists or if you are on a shared IP, consider reaching out to your email service provider, such as 17hats, for assistance in delisting or understanding the specific block.
Technical article
Documentation from Rackspace Support explains that a 550 5.7.1 error often indicates the sending IP address or domain is on a blocklist. To resolve this, identify the specific blocklist by looking at the bounce message details, then visit the blocklist's website to follow their delisting process. Proactive measures include reviewing email content for spam trigger words, ensuring proper SPF, DKIM, and DMARC records, and maintaining a clean sender reputation.
24 Dec 2024 - Rackspace Support
Technical article
Documentation from SendGrid Docs outlines that a 550 5.7.1 error due to blocklisting means the receiving server has rejected the email because the sending IP or domain is on a spam blocklist. To fix this, it's crucial to identify the specific blocklist mentioned in the bounce message. Once identified, users should visit the blocklist's removal page and submit a delisting request, while also addressing the root cause of the listing, such as poor sending practices or spam complaints.
11 Jun 2023 - SendGrid Docs
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