How can I tell whether something is blocking my connection to your mail servers?

We occasionally receive reports that a customer's mail program is unable to connect to our servers. In most cases, restarting your computer will solve this kind of problem.

If restarting the computer doesn't help, the rest of this page explains how to tell if the problem is with the mail program, or if something else (such as a firewall on your computer or at your ISP) is blocking the connections:

Restart your computer

As mentioned above, please try restarting your computer as a first step. This will fix many connection problems.

Try disabling your firewall

The next thing to try is temporarily disabling any firewall software you use. (What a firewall does is block certain connections. If some connections are mysteriously getting blocked, it may be caused by firewall software that has decided the connections are "suspicious".)

We have instructions explaining how to disable the Windows Firewall software and the firewalls included in various Norton Internet Security and Norton AntiVirus products. If you use different firewall software, please see the instructions that came with that software.

In particular, if you use a SonicWall firewall and your connections are being dropped when you send or receive certain kinds of email messages, an automatic update to the firewall rules is almost certainly interrupting the connection. Try disabling all email blocking, filtering and scanning features in the SonicWall.

If temporarily disabling the firewall allows you to connect to our servers, you should review the documentation that comes with the software to learn how to tell it to allow normal email connections with the firewall turned on. If you have trouble, please contact the company that makes the program for assistance.

Try changing your outgoing port number

If you are just having problems sending messages, and you can receive mail from other people, then your ISP may be blocking your outgoing connection. Check that your email program is set to use port 587 or 465 for outgoing mail. If it's using port 25, try changing the outgoing port number to 587.

After changing the port number, move (or delete) any messages in the outbox and try sending a new message. If successful, then try recreating the other messages (don't send the previous ones that were in the outbox).

Try a different mail program

The next thing we recommend if your mail program still can't connect is trying a different mail program to see if it works. A popular free mail program is Mozilla Thunderbird. You can download and install it at no charge, then follow our Thunderbird setup instructions to see if it works. If it does, you'll know that your connections aren't being blocked.

Check which wireless network you are using

If you are connecting to the Internet via a wireless network, your computer may have connected to a different wireless network than you expected it to, and the other network might be blocking your connections.

Try a text connection to our servers

If you can't get a different mail program to work, either, you can try a different kind of test. The instructions below explain how to make a text-based connection to our mail servers, mimicking what your mail program usually does invisibly.

You can do this in a few easy steps:

1. Enable telnet (Windows Vista, Windows 7, Windows 8, Windows 10)

Telnet is not installed by default on Windows Vista and later, so you may need to install it. You can skip this step if you use maxOS or Linux.

  • Click the Windows Start button, then choose Control Panel. (In Windows 8, type control panel at the Start screen and press enter.)
  • Choose Programs (this may be called Programs and Features).
  • Choose Turn Windows features on or off.
  • Check the Telnet Client checkbox.
  • Click OK, then finish the installation.

2. Open a command window.

To open a command window:

  • If you're using Microsoft Windows 7 or earlier, click the Start button, then choose All Programs > Accessories > Command Prompt, which will open a new window with a black background.
  • With Windows 8 or later, type command prompt at the Start screen and press enter.
  • With Mac OS X, open the "Terminal" application.

3. Type a "telnet" or "nc" command.

Once the command window is open, type this text and press "Enter" if you're having trouble with incoming mail:

telnet 110

If you’re using macOS High Sierra or later and you see a message saying “telnet: command not found”, use “nc” instead:

nc 110

The response may display several lines, but you should see a line that starts with "+OK", such as this:

+OK Dovecot ready

Similarly, if you're having trouble with outgoing mail, type this in a new, separate command window and press "Enter":

telnet 587

If you’re using macOS High Sierra or later and you see a message saying “telnet: command not found”, use “nc” instead:

nc 587

And you should see this line (among others) in the response:

220 ESMTP Postfix

(It's okay if the word "something" is a different word.)

If you don't see these lines in the response, contact us and let us know exactly what you do see, because it means that something is blocking your computer's connections to our mail servers. Please be sure to copy and paste all of the command window text into your message to us, since it's all important. We'll do our best to help you figure out what's causing the problem, although in some cases you may need to ask your network administrator.

(By the way, you can just close the command windows when you're finished with the tests above.)