What does the "error dialing remote address" bounce code mean and is it controllable?
Michael Ko
Co-founder & CEO, Suped
Published 21 Apr 2025
Updated 19 Aug 2025
7 min read
Encountering email bounce codes can be a frustrating experience, especially when the message is cryptic. One such bounce code that often puzzles senders is "error dialing remote address." It doesn't immediately tell you what went wrong or how to fix it.
This message typically indicates a fundamental network problem, preventing your sending server from establishing a connection with the recipient's mail server. It's akin to trying to make a phone call, but the line itself is dead or the number is unreachable.
Unlike some other bounce errors that point to content issues or recipient mailbox problems, this one is about the communication channel itself failing. Understanding its root causes is key to determining how much control you have over resolving it and improving your email deliverability.
Understanding the "error dialing remote address" bounce
When you see the "error dialing remote address" bounce, it means the SMTP client on your sending server (or your email service provider's server) attempted to initiate a TCP connection to the receiving mail server, but it failed to do so within the allotted time. The common phrase often includes an "i/o timeout" indication, which specifically points to this connection failure.
This isn't an issue related to DNS resolution, where the domain name can't be translated into an IP address. Instead, it means the IP address was successfully looked up, but the server couldn't establish the initial handshake over port 25 (the standard port for SMTP) with the target server. It's a low-level network communication problem, typically at the TCP/IP layer.
This type of error is often categorized as a soft bounce, meaning it's a temporary failure. Mail servers are usually configured to retry sending the message several times over a period. However, if the underlying issue persists, the soft bounce will eventually turn into a hard bounce, and the message will be permanently undeliverable. Understanding bounce message error codes is crucial for effective email management.
Common causes of this error
There are several reasons why your server might fail to connect to a remote address. These issues are typically on the recipient's side, but sometimes your network configuration or sender reputation can play a role. Here are some of the most common culprits:
Recipient server offline: The most straightforward reason. The recipient's mail server might be temporarily down for maintenance, experiencing a power outage, or simply overloaded, making it unreachable.
Firewall or network issues: A firewall on the recipient's network could be blocking incoming connections on port 25, or there could be general network congestion or routing problems between your server and theirs.
IP blocklist (blacklist): Although less common for this specific error, if your sending IP address is on a public or private email blacklist (or blocklist), the recipient server might simply drop the connection attempt without a more specific rejection message. However, more often a blocklist triggers a clearer rejection.
Incorrect MX records: If the domain's MX (Mail Exchange) records are misconfigured or point to a non-existent server, your server might attempt to connect to an invalid address, leading to a timeout. This is less about DNS resolution failing and more about the resolved IP not actually hosting a mail server. You can find out more about no MX bounce reasons in our knowledge base.
In many cases, these are transient issues, which is why mail servers implement retry mechanisms. However, persistent "error dialing remote address" bounces to a particular domain can indicate a deeper, ongoing problem with that domain's mail infrastructure.
Is this bounce code controllable?
The level of control you have over this bounce code largely depends on the root cause. If the issue lies with the recipient's mail server being temporarily offline or experiencing network problems, there's very little you, as the sender, can do directly to fix it. Your mail server will automatically retry sending, and if the recipient server comes back online, the email will eventually be delivered.
However, there are aspects you can control to minimize the chances of your emails encountering such issues or to react effectively when they do. This primarily revolves around maintaining a robust sending infrastructure and a strong sender reputation. For instance, if you are using a third-party email service provider like Simplero, they usually handle the retry logic automatically.
If you manage your own mail server, you can configure your sending software to handle retries and timeouts appropriately. Ensuring your server has proper DNS resolution configured and is not experiencing its own network issues is also within your control. You should also regularly monitor your domain's health and email domain reputation.
What you can control
Sending infrastructure: Ensure your mail server or ESP has stable network connectivity and sufficient resources. Proper email authentication (SPF, DKIM, DMARC) can also indirectly help by signaling trustworthiness.
Bounce handling: Configure your system to adequately retry soft bounces and remove addresses that repeatedly hard bounce. This prevents wasted resources and helps maintain a clean list.
List hygiene: Regularly clean your email lists to remove invalid or inactive addresses, reducing the chances of hitting non-existent or problematic domains.
What you can't directly control
Recipient server status: You cannot directly influence whether the recipient's mail server is online, overloaded, or undergoing maintenance.
Recipient network configurations: Firewall rules, network congestion, or routing issues on the recipient's side are beyond your influence.
IP-based blocking: If your IP is on a private private blocklist at the recipient's end, you cannot directly remove it, though improving your sender reputation may help over time.
Mitigating the impact and improving deliverability
While you can't force another server to come online, you can take proactive steps to minimize the impact of "error dialing remote address" bounces and improve your overall email deliverability. The key is to focus on what is within your sphere of influence.
Best practices for minimizing connection errors
Monitor bounce rates: Keep an eye on your bounce logs. If you notice a sudden spike in "error dialing remote address" bounces to a particular domain, it might indicate a problem on their end that is affecting multiple senders.
Check your network: Ensure your own sending infrastructure has stable network connectivity. An unstable connection from your end can also lead to these timeouts.
Sender reputation: A good sender reputation can sometimes help. While not a direct fix for network issues, a trustworthy sender is less likely to be aggressively filtered or have connections dropped by receiving servers. Learn more about recovering domain reputation.
Communication with recipients: If you have another way to contact the recipient (e.g., phone, alternative email), you might inform them of the issue, though this is only practical for specific high-value communications.
Remember, email deliverability is a complex ecosystem. While some bounces are clearly within your control (like content issues or invalid recipient addresses), others, such as network timeouts, often point to external factors. Your best strategy is to maintain a healthy sending environment, understand the various SMTP bounce codes, and react appropriately when issues arise to ensure your messages reach their intended destinations.
Views from the trenches
Best practices
Maintain proper network configuration and sufficient bandwidth for your sending server.
Use a reputable Email Service Provider (ESP) that actively manages their network health.
Implement robust bounce handling to automatically retry and remove persistently unreachable addresses.
Regularly monitor your email logs for recurring 'error dialing remote address' bounces.
Common pitfalls
Ignoring recurring 'error dialing remote address' bounces, assuming they are always temporary.
Not having adequate network monitoring on your sending server or infrastructure.
Sending to very old or uncleaned email lists, increasing the chance of hitting problematic domains.
Overlooking your own server's firewall rules that might inadvertently block outbound SMTP.
Expert tips
An expert notes that this bounce indicates a TCP connection timeout, not a DNS issue.
Another expert suggests that the 'dialing' terminology might indicate a Go language backend.
A marketer highlights that for SendGrid users, this issue is usually beyond their control.
An expert emphasizes that I/O timeout is a protocol-level issue, not a reputation problem.
Expert view
Expert from Email Geeks says that this bounce means the SMTP client failed to establish a connection with the remote host due to a TCP connection timeout, not a DNS-related issue.
2020-02-13 - Email Geeks
Expert view
Expert from Email Geeks says that the term "dialing" suggests the use of Go language in the email service provider's application.
2020-02-13 - Email Geeks
Navigating connection errors for better deliverability
The "error dialing remote address" bounce code is a clear indicator of a failure to establish an initial TCP connection with the recipient's mail server. While often temporary and automatically retried by a well-configured sending system, it can sometimes point to persistent issues on the recipient's side.
Your direct control over this specific error is limited since it often stems from external network or server problems. However, you can significantly mitigate its impact by maintaining a robust sending infrastructure, diligently monitoring your bounce logs, and adhering to best practices for email deliverability. By focusing on the health of your own sending environment, you ensure that you're doing everything possible to get your emails through, even when faced with temporary external hurdles.
