Summary
Email delivery issues, particularly those from a service provider like SendGrid, can be frustrating, especially when they involve unusual error messages and seemingly truncated recipient addresses. The errors unable to get mx info: failed to get IPs from PTR record: lookup <nil>: unrecognized address and error dialing remote address: dial tcp... i/o timeout point to underlying network or DNS problems that prevent the email from reaching its destination. The observed truncation of email addresses suggests a potential issue with how recipient data is being processed or transmitted, leading to attempts to send to invalid or incomplete domains.
Key findings
- DNS resolution issues: The error unable to get mx info: failed to get IPs from PTR record indicates a problem with the DNS (Domain Name System) lookup for the recipient's domain or the sender's IP address, specifically concerning PTR records.
- Connection timeouts: An i/o timeout suggests that while a mail exchange (MX) record or A record might exist, the sending server (SendGrid's, in this case) was unable to establish or maintain a connection with the recipient's mail server.
- Truncated addresses: The appearance of truncated recipient email addresses (e.g., client@email.c instead of client@email.com) is a critical symptom, likely leading to these DNS and connection errors because the destination domain becomes invalid. This can cause emails to be bounced with errors like 'domain does not exist'.
- Data source integrity: The primary suspect for truncation, if not occurring within SendGrid itself, is an issue with the original email address data source or the process of parsing that data before it reaches SendGrid.
Key considerations
- Validate recipient data: Thoroughly inspect the source of your email addresses to ensure they are correctly formatted and complete before being sent to SendGrid. Look for any data export, API integration, or database issues that might introduce truncation.
- Test DNS resolution: Perform various DNS lookups for the affected domains, including MX and A records, from different network locations. This can help confirm if the issue is with the recipient's domain DNS or specific network paths. You can also review how to run an email deliverability test.
- Contact SendGrid support: If internal data validation confirms that addresses are not truncated prior to SendGrid, escalate the issue with SendGrid's support team. Provide them with the exact error messages and examples of truncated addresses to investigate potential internal processing bugs.
- Review ISP connectivity: Investigate if there are any network connectivity issues or firewall restrictions between SendGrid's sending IPs and the recipient's mail servers. This might require coordination with both SendGrid and the recipient's ISP. For more general advice on common delivery failures, see this Twilio blog post on email delivery failure causes.
- Improve deliverability: To prevent similar issues and improve overall delivery rates, ensure your email addresses are valid. Understanding why emails bounce with domain does not exist errors is key.
What email marketers say
Email marketers often encounter perplexing delivery issues, and those involving truncated addresses through platforms like SendGrid are particularly challenging. Many marketers report discrepancies between their stored data and what appears in bounce messages, suggesting potential parsing or transmission problems. Their focus often quickly shifts to validating the integrity of their own data sources and the precise nature of the error messages returned by the ESP. It's a common concern that such issues lead to an inability to reach crucial clients, impacting campaign effectiveness and client communication.
Key opinions
- Inconsistent data: Marketers frequently find that while their internal databases hold correct and complete email addresses, delivery errors indicate a truncated version, leading to confusion about where the truncation occurs.
- Error message interpretation: Understanding the specific SendGrid error messages, such as those related to MX info or I/O timeouts, is crucial for marketers to debug delivery failures effectively.
- Impact on campaigns: Non-delivery due to truncated addresses directly impacts marketing campaign success and client communication, making a quick resolution a high priority.
- Seeking community insights: Many marketers turn to peer communities and forums to see if others have experienced similar truncation or delivery issues with SendGrid or other ESPs.
Key considerations
- Data pipeline review: It is essential to review the entire data pipeline, from CRM or database to SendGrid, to identify any points where email addresses might be incorrectly parsed or truncated, potentially explaining why SendGrid links are broken.
- SendGrid support engagement: If internal checks confirm data integrity, contacting SendGrid support with specific examples and error logs is necessary to ascertain if the issue is on their side.
- Understanding truncation context: Determine if the truncation occurs in the email body (often leading to messages being clipped in Gmail) or the recipient address itself, as this drastically changes the troubleshooting path.
- General deliverability health: This type of issue can be a symptom of broader deliverability challenges, highlighting the importance of regularly monitoring and troubleshooting overall email performance. More generally, learn why your emails fail.
Marketer view
Email marketer from Email Geeks reports noticing that a few emails are not getting delivered to clients despite their database having the correct email address. They express confusion over the issue, particularly given the accuracy of their internal records, which use the API version for contacts, not marketing campaign contacts.
Marketer view
A marketer from Email Geeks indicates observing an email address that was chopped, changing from client@email.com to client@email.c. They found this truncation strange and questioned what might be causing it within SendGrid, as it directly led to delivery failures for those specific recipients.
What the experts say
Email deliverability experts highlight that issues like truncated email addresses and related DNS or connection errors are fundamental to email infrastructure. They often point to misconfigurations in DNS records, such as PTR, MX, or A records, as primary culprits. While truncation of a recipient address by an Email Service Provider (ESP) is unusual, experts suggest it could be a symptom of malformed data being fed into the system or an issue during the ESP's internal processing. Troubleshooting these problems typically involves a deep dive into network diagnostics and a careful review of how data is handled from sender to recipient.
Key opinions
- DNS criticality: Experts universally agree that accurate DNS configuration, including PTR records for IP addresses and MX/A records for domains, is paramount for successful email delivery. Errors in these can lead to messages being undeliverable.
- Truncation as a symptom: While an ESP truncating an address is rare, experts suggest it's more likely a display issue in bounce messages or a problem with the data being supplied to the ESP rather than the ESP itself intentionally chopping addresses.
- Network connectivity: I/O timeouts are clear indicators of network problems preventing connection or transmission, which could stem from firewalls, routing issues, or the recipient server being overloaded or unresponsive.
- Source data integrity: The first step in debugging such issues should always be to verify the integrity and correct formatting of the email addresses in the sender's own database before they are handed off to the ESP.
Key considerations
- Comprehensive DNS checks: Perform exhaustive DNS checks from various points of origin to diagnose if the DNS issues are localized or widespread. This includes verifying MX, A, and PTR records for both sending IPs and recipient domains. For more details, consult a simple guide to DMARC, SPF, and DKIM.
- ISP engagement: If DNS resolution or connection timeouts persist, engaging with the recipient's Internet Service Provider (ISP) or network administrators can provide deeper insights into their specific blocking or filtering mechanisms.
- Error message analysis: Carefully analyze the full bounce message and delivery logs provided by SendGrid. The truncation might only be present in the bounce report, and the actual send attempt used the correct address, but failed due to other reasons like SPF TempError.
- Data format verification: Ensure that the email addresses are being passed to SendGrid via API or SMTP in the exact format required, without any unexpected character limits or encoding issues.
Expert view
Deliverability expert from Spamresource.com emphasizes the critical importance of proper DNS configuration, including PTR records, for successful email delivery. They note that misconfigured DNS can lead to various delivery failures, including an inability to resolve recipient domains or establish necessary connections, directly impacting deliverability rates.
Expert view
Email deliverability consultant from Wordtothewise.com explains that 'i/o timeout' errors often indicate network connectivity issues between the sending server and the recipient's mail server. This can suggest potential firewall blocks, incorrect routing, or an unresponsive recipient server preventing the full SMTP handshake and message transmission.
What the documentation says
Official documentation from email service providers like SendGrid and deliverability resources emphasize the importance of correct email formatting, robust DNS configurations, and understanding various bounce codes. While direct documentation on ESPs truncating recipient addresses is rare, guides on common delivery failures often point to issues with invalid recipient addresses, DNS resolution problems, and network timeouts. These documents typically outline best practices for ensuring data quality and diagnosing common roadblocks to successful email delivery.
Key findings
- Invalid recipient addresses: Documentation frequently lists invalid recipient addresses as a primary cause of bounces, which would include addresses that are truncated or malformed.
- DNS lookup failures: Errors like unable to get mx info are directly attributed to issues where the sending server cannot resolve the recipient domain's mail exchange records.
- Connection timeouts: Documentation explains that I/O timeouts occur when a connection attempt to the recipient's server fails to complete within a specified timeframe, often due to network issues, firewalls, or an unresponsive server.
- Message clipping vs. address truncation: While some documentation discusses message clipping for email content, it's distinct from address truncation, which directly impacts routing.
Key considerations
- Adherence to best practices: SendGrid and other ESPs publish guides on mastering email deliverability, which often include sections on email address validation, proper DNS setup, and handling bounces.
- Error code meaning: Referencing the specific error codes and messages in the documentation helps clarify the exact nature of the delivery failure and guides troubleshooting steps.
- Impact of URL length: While this case involves address truncation, it's worth noting that URL length can affect deliverability, a related content issue that documentation covers.
- Debugging delivered but unseen emails: Some documentation also addresses scenarios where emails are reported as delivered but don't appear in the inbox, offering insights into filtering and folder placement by recipient mail servers.
Technical article
SendGrid support documentation explains that emails sent to Gmail inboxes might be clipped if the message body exceeds a certain character limit, typically 102KB. This clipping primarily affects the visibility of content, showing a '[Message clipped]' link rather than preventing delivery, but highlights how length constraints are managed by Mailbox Providers (MBPs).
Technical article
The SendGrid article on 'Mastering Email Deliverability' outlines various reasons for email non-delivery, including ISP blocking of IP addresses, server issues, and problematic message content. It underscores that understanding these factors is crucial for maintaining a healthy sending reputation and ensuring messages reach their intended recipients.
Related resources
5 resources
Related pages
Why are emails bouncing with 'domain does not exist' or 'invalid sender domain' errors?
Why are my SendGrid links broken and how do I fix it?
Why your emails fail: expert guide to improve email deliverability [2025]
How to run an email deliverability test: a proven checklist
A simple guide to DMARC, SPF, and DKIM
Demystifying the SPF temperror in your DMARC reports
How does URL length affect email deliverability?
Email deliverability issues: getting your messages to the inbox in 2025
Boost email deliverability rates: technical solutions from top performing senders
What RFC 5322 says vs. what actually works
