Issues Sending Email

If you’re having problems sending email, it may be something as simple as a wrong password or a port being blocked. Here are some common reasons you may have issues sending email.

Wrong password

Even if you’re absolutely sure the password was entered right, check again. If you’re thinking “It has to be right, because I copied and pasted it” you might be surprised. Many times, especially in Firefox and certain other applications, when you paste in the password an extra space will be inserted. One single, simple blank space at the end of your password could be the culprit.

Secure connections and ports

Some email service providers require the use of a secure connection in order to connect to SMTP. You need to make sure this option is selected in the email client you’re using. For example, in Outlook, there’s an option for “This server requires a secure connection”.

Some servers may also require connecting on port 465 (secure) vs 25 (insecure). If neither of these ports work, you can also try the mail suspension port – 587.

Speaking of ports…. Port 25

Many ISPs will have port 25 blocked. So if you’re trying to use port 25 and have problems, you should make sure this isn’t the case.


For Windows

Hit the Windows key+R to bring up the command prompt box and type in:



For Mac

  1. Go to Mac HD
  2. Go to Applications
  3. Go to Utilities
  4. Type this and hit enter:


For Linux

Using a terminal emulator, execute this:



If you get a message that has 220 in it or “connected” then it should open and ready to use. But if you get an error, couldn’t connect or no response at all then it’s blocked.



If you see an error that mentions authentication then you may have the wrong authentication method setup. Most email programs provide different options for password authentication, including:

  • Encrypted
  • Kerberos
  • Normal or plain text

SMTP crash

If you see an error that mentions something about server unknown, make sure you have the servername correct and there’s no problem with the resolution of the server.


Ping the server


  • If it responds to the ping, it’s the mail server not responding
  • If it doesn’t ping either, the entire server is not responding and rebooting may help
  • If it doesn’t resolve at all, it’s likely something wrong with the DNS of the domain/host – look it up on



Your IP may have been blacklisted. Use one of these blacklist checkers to see if your server or IP has been blacklisted:




You may be sending SPAM whether you realize it or not. Please see this for more information.


Mail Queue

The mail queue may be full or stopped. You only have access to this through WHM though.


  1. Go to WHM
  2. Go to Mail Queue Manager under Email

Here, you’ll be able to view emails that are in the queue and see how many there are. You can also attempt to deliver undelivered messages that are sitting here. If an attempt was made to send an email to an incorrect/unavailable address, they’ll be here. You should manually delete these emails to clear them out.   


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