Knowledgebase: Email
Why can’t I Send Domain Email through my email client?

If you are able to receive email but not send, it's possible that your Internet Service Provider (ISP) is blocking your outgoing mail server.

Many ISPs limit access to port 25 on their connections in order to curb spam being sent via their networks. This means that while you're connected to their network, you can only use their outgoing mail server on port 25 to send mail. Therefore, will not work as long as you're physically connected to the ISP's network.

The following is a brief list of steps you can try to help you troubleshoot and hopefully allow you to send email.

Check your Settings

In order to send mail through your 3dcart account, your email program must be set to use 3dcart's outgoing mail server. This is specified as "" using port 25. Most email programs will automatically default to using port 25 on the connection to send, so in most cases you'll only need to specify the outgoing mail server itself.

If your domain's DNS is pointed to 3dcart, you can also use mail.[yourdomain].com instead.

Change the Port

As mentioned, most ISPs block the outgoing mail server by limiting access to port 25. The second step you can try is to use an alternate SMTP port on your email program. To do this, edit your existing mail settings (in your email program) so that the outgoing mail server uses port 587 instead of 25.

Every email client program will be different, but you can generally change the port in the "Settings" area of the individual mailbox account created on the program. For example, the screenshot below was captured in the Mozilla Thunderbird email program. Check with your specific Email Program's manufacturer to learn how to access the port setting.

Use your ISPs outgoing mail server

If neither port 25 nor port 587 work, then you will be required to use your ISPs outgoing mail server instead. Your individual ISP's support team should be able to provide you their SMTP server information.


  • Q: How can I confirm if port 25 is blocked?
  • A: While connected to your ISP, try the following:
    1. Access your computer's command line interface
    2. Type telnet 25
    3. hit enter.
      • If your outgoing port is not blocked, you will see message lines with 220 listed at the start of the line. (i.e. 220
      • If your outgoing mail port is in fact blocked, you will see an obvious connection error message or no message at all.

To access your computer's command line.

  • Windows users - Click Start >Run >Type in CMD.
    (for Windows 7 - Click Start button >Type CMD into the search field)
  • Mac users - Use the terminal application in the Applications >Utilities folder.
  • Q: If I use my ISP's outgoing mail server, will my email address still be
  • A: Yes. All you are doing is using the available server to send mail through your ISP. The message is simply taking a different path to its destination but the message itself is still the same. The email address used on the messages will still be whatever email address the mail account is set for.
  • Q: What if I can't send OR receive?
  • A: To clarify, port 25 blocking only affects your ability to send mail. It will not have any bearing on incoming messages. If you are unable to send or receive messages using your configured settings, you might have additional issues to address. Please contact support for further assistance if this is the case.

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