MozillaZine

Connection errors - POP3

From MozillaZine Knowledge Base

This article was written for Thunderbird but also applies to Mozilla Suite / SeaMonkey (though some menu sequences may differ).

This article lists the error messages that you might see when you try to connect to a POP3 server to get mail. For each error message it identifies possible causes.

Getting mail from the POP3 server happens in stages. Different things can go wrong at each stage, so each stage has different error messages.

When a connection fails, Thunderbird provides you with up to three pieces of information about the failure. If you have to ask for support (for example, in a forum or from a helpdesk), ensure that you provide all the information:

  • The status message in Thunderbird's status bar. This tells you the stage that Thunderbird reached when the error occurred.
  • The error message provided by Thunderbird.
  • An embedded message from the server. Thunderbird includes this in its error message.

Note:  If an error message shows the server name as "localhost", it usually means that you are using a webmail extension or an anti-virus program. In this case the error might be coming from that program, not from the real server.

Contents

Thunderbird errors

This section lists the stages that Thunderbird goes through when it connects to a POP3 server to get a message, and it lists the possible error messages for each stage.

Lookup

Thunderbird looks up the POP3 server's name to find its network address (IP address). The lookup service (DNS) is usually provided by your ISP as part of your Internet connection. The status message at this stage is "Looking up..."

Failed to connect to server server name.

  • The server does not exist (but it might exist when you are connected to some other network).
  • You typed the server name wrongly. (Even an extra space can make it fail.)
  • Your ISP's DNS is broken. Try disconnecting and reconnecting, or contact your ISP.

Connecting

Thunderbird connects to the POP3 server, and the POP3 server responds. The status message at this stage is "Connecting..."

Could not connect to server server name; the connection was refused.

  • You specified the wrong server. The server you specified exists, but it is not a POP3 server.
  • You specified the wrong port number. Ask whoever runs the POP3 server what the correct port number is.
  • The server is down. This is usually temporary. If it persists, contact whoever administers the server.
  • Your firewall is blocking the port.
  • See also the Security section, below.


An error occurred with the POP3 mail server. Mail server server name responded: message
(Where message might be blank.)

  • You specified the wrong server. The server you specified exists, but it is not a POP3 server.
  • You specified the wrong port number. Ask whoever runs the POP3 server what the correct port number is.
  • The server is down. This is usually temporary. If it persists, contact whoever administers the server.

Security

If your settings require it, Thunderbird creates a secure connection using TLS or SSL. The status message at this stage is "Connected..."

Connection to server server name timed out.

  • You specified SSL, but the server does not support it. In this case Thunderbird makes a connection, but its attempt to use SSL times out, so the status message is "Connected...", and there is a delay (normally 60 seconds) before you see the error message.


Unable to establish TLS connection to POP3 server. The server may be down or may be incorrectly configured. Please verify that your Mail/News account settings are correct and try again.

  • You specified TLS, but the server does not support it.

Logging in

If your settings require it, Thunderbird logs in by sending your username and password. If the server does not accept the username and password combination, then Thunderbird asks you for the password again. If your password does not work, there might be various reasons:

  • You typed the wrong password. Perhaps it is case sensitive.
  • You specified the wrong user name. Perhaps it needs to be your entire e-mail address, or perhaps only part of your e-mail address.
  • You are connecting to the wrong server, and this server does not recognize your username.
  • Your user name is not yet registered on the server.
  • The server is broken.


Mail server does not support secure authentication.

  • You checked the box "Use secure authentication" in your account settings, but the server does not support any of the secure authentication methods that Thunderbird supports. Thunderbird supports GSSAPI, Kerberos, CRAM_MD5, DIGEST-MD5, NTLM, and APOP. NTLM is also called Secure Password Authentication (SPA) or Windows Integrated Login.


Mail server does not support secure authentication or you have entered an incorrect password. Please check your password, or turn off secure authentication in the account settings for your mail server.

  • You checked the box "Use secure authentication" in your account settings, but the server does not support it. (Specifically, Thunderbird tried to use APOP but the server did not cooperate.)


An error occurred with the POP3 mail server. Mail server server name responded: message

  • The server requires secure authentication, but you did not specify secure authentication in your account settings.


Error getting mail password.

  • Thunderbird's password manager failed to get your password. Perhaps your Thunderbird profile is damaged.


You have not supplied a username for this server. Please provide one in the account setup menu and try again.

  • Your account settings in Thunderbird are wrong.
  • Your Thunderbird profile is damaged.


Sending of username did not succeed.

  • You specified the wrong user name. Perhaps it needs to be your entire e-mail address, or perhaps only part of your e-mail address.
  • You are connecting to the wrong server, and this server does not recognize your username.
  • Your user name is not yet registered on the server.
  • The server is broken.


Sending of password did not succeed.

  • You typed the wrong password. Perhaps it is case sensitive.
  • You specified the wrong user name. Perhaps it needs to be your entire e-mail address, or perhaps only part of your e-mail address.
  • You are connecting to the wrong server.
  • The server is broken.

Getting mail

Thunderbird gets the messages.

The POP3 server server name does not support UIDL, which is needed to implement the "Leave on Server" and "Maximum Message Size" options. To download your mail, turn off these options in the Mail Server panel of Preferences.

  • The server is old, or badly configured.


The POP3 mail server (server name) does not support the TOP command. Without server support for this, we cannot implement the "Maximum Message Size" preference. This option has been disabled, and messages will be downloaded regardless of their size.

  • The server is old, or badly configured.


The STAT command did not succeed. Error getting message number and sizes.

  • Server failure


The RETR command did not succeed. Error retrieving a message.

  • Server failure


The LIST command did not succeed. Error getting the ID and size of a message.

  • Server failure


The DELE command did not succeed. Error marking a message as deleted.

  • Server failure


Unable to write the email to the mailbox. Make sure the file system allows you write privileges, and you have enough disk space to copy the mailbox.

  • Thunderbird failure. Its possible the "inbox." file used to store the messages for your inbox folder is read only. However, typically this problem occurs due to an attempt to download a malformed message. See Unable to write the email to the mailbox for more information.

There was an error downloading the following message:
From address
Subject: subject
This message may contain a virus or there is not enough disk space. Skip this message?

  • Thunderbird failure. Perhaps your Inbox file is read-only.

The "may contain a virus" part of the message is probably misleading.

Network errors

Things can go wrong with the network at any stage in getting a message. These errors are not related to the POP3 server, but they can interrupt communication with the server, so that getting messages fails.

A communications error occurred: error message Please try again.
or:
A network error occurred while receiving data. (Network Error: error message) Try connecting again.

  • There is a problem with your network connection. Try disconnecting and reconnecting. If it still does not work, contact your ISP.

See also