Whenever I sent an email from my Outlook client, it bounces with this ‘socket error 10060 connection timed out’ SMTP error. What’s wrong?
That was a recent support ticket received at our Server Support department where we resolve support queries for web hosts.
Website owners often face this error when they send emails from email clients like Outlook, Thunderbird, etc.
There’s an error code 10060, what’s that?
And, the message shows connection timed out, but why?
Today, we’ll see the answers to all these questions.
‘socket error 10060 connection timed out’ SMTP error – What’s this?
Before we move on to the reasons for this error, let’s first get an idea of this error.
In a normal mail delivery, mail goes from the sender, to the sending MX, and to the recipient’s MX, and then to the recipient.
How Email Works?
The Socket Error 10060 indicates that the connection to the recipient server times out.
In other words, the sending server doesn’t receive a response from the recipient server.
For instance, website owners see the complete error message like this:
Error Message: "There was an error connecting to the email server. Email could not be sent. Socket Error #10060. Connection Timed Out."
But, this error only stops the user from sending emails, and receiving will work fine.
Now, let’s discuss the top 5 reasons for this error and how our Server Support Engineers fix it.
‘socket error 10060 connection timed out’ SMTP error – Causes and Fixes
A number of reasons can lead to this ‘socket error 10060 connection timed out’ SMTP error.
Let’s see the main causes identified in our debugging process and how we fix them.
1) Wrong SMTP host and port
This error occurs mainly when the outgoing mail server settings are wrongly setup in the email clients like Outlook, Windows Mail, etc.
Sometimes, a typo in the hostname or an inactive mail server leads to this error.
Similarly, the default SMTP port is 25, but some email providers use custom ports, like 587, to avoid spam.
In addition to that, some email servers are configured to allow emails only via SSL port 465.
So, incorrect hostname or incorrect port entry in the email client settings may cause email delivery errors.
Solution
Firstly, our Hosting Engineers, ensure the DNS connectivity of the SMTP host with the below command.
dig mail.domain.com
Further, we use the below command to identify the correct SMTP port and its connectivity.
telnet mail.domain.com 25
After that, we cross-check and correct the SMTP settings in the email client.
[We know that emails are critical for your business. Are you not sure about your email client settings? Our Support Experts are here for your help.]
2) Improper SMTP authentication
Similarly, this error may occur due to authentication problems at the sender end.
All SMTP servers implement authentication process to protect against spamming and email abuse.
In other words, users are only allowed to connect to the SMTP server, and send emails after successful authentication.
And, this authentication is integrated with email clients as well.
So, if a sender tries to connect to the SMTP server without authentication, the connection will be refused with ‘socket error 10060 connection timed out ‘ SMTP error.
Solution
Our Support Engineers check the email client settings, and ensure that SMTP authentication is enabled in the sender’s email client.
For example, in Outlook 2007, we verify these settings from Tools > Account Settings > More settings > Outgoing server tab > My Outgoing server (SMTP) requires authentication.
How to enable My SMTP authentication in Outlook?
3) ISP firewall issues
Many ISPs now block traffic through port 25 to minimize spam, and this is one of the most common reasons for this error.
Solution
Our Support Engineers always ask the users to get back with the traceroute results to the email server from their PCs.
This helps us to identify if there are connectivity issues in any of the intermediate networks between the mail server and user PC.
If we find issues at ISP level, the user must contact the ISP end to remove the block on that port.
But, the ideal solution we recommend is to use the SMTP server recommended by the ISP.
4) PC firewall issues
Third party firewall or antivirus installed on the user’s PC can block the connection from certain applications.
In other words, it blocks connections to certain IP ranges and can sometimes blocks the mail server IP as well.
So, customer’s won’t be able to connect to the mail server from their email client and see ‘socket error 10060 connection timed out’ SMTP error.
Solution
In such cases, we get the telnet results from the user’s PC to the mail server.
For example, we use the below command to check the connectivity to the mail server “mail.domain.com” on port 25.
telnet mail.domain.com 25
And, if the firewall hinders the connection, we recommend the customer to disable the firewall and give a try.
If it works, users must tweak their PC firewall settings.
5) Infected PC
This is not a common reason but can happen at times.
‘socket error 10060 connection timed out’ SMTP error can pop up when your local PC is infected with malware.
Solution
In this case, our Support Engineers advise users to perform a full scan on their PC with a standard anti-virus.
And, remove any spyware, trojan or viruses detected in the system.
This list is not complete. There could be many more reasons for this error.
But a detailed log analysis is required to identify the exact reason behind this error.
So, if you need help, click here to get a Support Expert to look into your email issue.
Conclusion
In short, ‘socket error 10060 connection timed out‘ SMTP error may occur due to incorrect email client settings, firewall restrictions, and more. Today, we’ve discussed the top 5 reasons for this error and how our Server Support Engineers fix them.
we called our ISP, and they were not blocking , turns out it was the ADTRAN / ISP modem devices, had to be rebooted.