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Cannot send e-mail, server has unexpectedly terminated the connection, connection has failed, cannot connect to smtp and similar errors.

You have LinkU Systems e-mail setup in your Outlook or other mail program and get one of the following errors when attempting to send mail through the LinkU Systems outgoing mail server:

  • Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity. Account mail Server SMTP <emailname>...
  • The TCP/IP connection was unexpectedly terminated by the server. (Account: <account name>, SMTP Server: <server name>...
  • The connection to the server has failed. Account <account name>, server, <server name>, protocol, port 25 (or 587)...
  • Your outgoing (SMTP) e-mail server has reported an internal error. If you continue to receive this message, contact your server administrator or Internet service provider (ISP).

Possible Cause #1:
You have not updated your outgoing mail server to the new settings after the e-mail transition. This includes the outgoing mail server and your port number may still be pointing to port 587.

Possible Cause #2:
Recently, many internet service providers (ISPs) have began blocking 3rd party SMTP port 25, such as access to the LinkU Systems, Inc. outgoing mail server, therefore causing one of the above errors.

Solution #1:
Verify you are using the correct outgoing mail server, or

Try changing the SMTP port in your e-mail program. If you are using the old port 587, or port 25, change the SMTP port to 2500.

To do this in Outlook XP / Outlook 2003, do the following:

  1. Click on "Tools" and select, "E-mail Accounts".
  2. Select "View or change existing e-mail accounts" and click "Next >".
  3. Select the account you would like to modify and click, "Change...".
  4. Click on "More Settings...".
  5. Click the "Advanced" tab.
  6. Change the Outgoing server (SMTP) port to 2500 and click "OK".
  7. Click, "Next >".
  8. Click, "Finish".

Solution #2:
Change the outgoing mail server (SMTP) for your LinkUSystems account to the outgoing mail server used by your Internet Service Provider (ISP). You must change this in your Outlook or E-mail program settings. You may have to contact your internet provider for support on how to properly set this up and/or their login information.

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