Whenever I attempt to send or forward an email in Outlook Express the following message appears: ‘Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity. Account: , Server: , Protocol: SMTP, Port: 25, Secure(SSL): No, Error Number: 0×800CCC0F’. The incoming and outgoing email servers are correct, as specified in the ISPs setup documentation. I have also increased the server timeout to 5 minutes, but the problem still remains. There are no problems receiving emails. The computer is running Windows XP.

Since you have verified the server configuration is correct, the cause of the problem is unlikely to be related to the Outlook Express configuration. In fact, the root cause of this issue is unlikely to be Outlook Express. The most likely cause of the problem is a third-party program, such as antivirus or firewall utilities, which are preventing Outlook Express from accessing the outbound mail server. So, we need to find whether any such programs are causing the problem, and identify which program is the culprit.

The first stage in identifying the cause is to temporarily disable any third-party antivirus, firewall, and security software running on the computer. Be warned, you will need to keep your computer connected to the internet during this process (so you can test whether the problem is fixed), but you are disabling your security software which potentially leaves the computer vulnerable to attack. Before beginning this procedure you should enable the Windows XP Firewall so you have at least a basic level of protection. The Windows XP Firewall can be enabled by going to the ‘Start’ menu > ‘Control Panel’ and open the ‘Windows Firewall’ control panel (you may need to first change to ‘Classic’ view if you are currently displaying the control panel in ‘Category’ view). In the Windows Firewall control panel, make sure the firewall is set to ‘On’.

Once the Windows Firewall is enabled, you can shutdown/disable the third-party security software. First, if you have a virus scanner which automatically scans outbound emails (most virus scanners have this function) then try disabling the outbound scanning function. The location of this feature will vary depending on the particular software you are running, but should generally be in the antivirus advanced settings. Once the outbound email scanning is disabled try sending an email from Outlook Express. If the message sends correctly, then the antivirus software seems to be causing the problem. In this case, I can’t provide any specific advice as I do not know what antivirus package you are running. However, there are a few generic suggestions you could try. First, reinstall the antivirus software. Perhaps a file or setting has become corrupt, which is causing the problem. Second, check whether an updated copy of the antivirus software is available. While upgrading will not be a guaranteed fix for the problem, there is a chance this could resolve the problem. Third, you could leave the outbound email scanning feature of the antivirus software disabled. Some would argue this feature is an extra-level of protection, and is not absolutely necessary. If the real-time scanning feature of the antivirus package, which scans all files for viruses which are opened on the system, does not detect any viruses on the computer then they should not be transmitted by email. While this is not ideal, as the more protection the better, this might be your only option in the short-term if you are unable to find the root cause of the problem. However, make sure you leave the inbound email scanner enabled as this is absolutely essential to scan inbound emails for viruses. Since email is a very common way for viruses to spread, scanning your inbound email for viruses is absolutely critical.

However, should disabling the antivirus outbound email scanning feature not resolve the problem, the next possible cause is a third-party firewall. If you are running a third-party firewall (e.g. ZoneAlarm, Norton, McAfee) try disabling the firewall to see whether the problem persists. If the problem ceases, obviously the firewall is causing the problem. In this case, it could be a firewall rule or misconfiguration causing the sending of emails to be blocked. Again, I can’t provide specific advice since I don’t know the exact configuration of your computer. So, you will need to explore the firewall settings yourself to find the configuration item(s) which are causing the problem.

However, as a security feature, some firewalls do not allow themselves to be easily disabled. In this case, you could try reinstalling the firewall software. This should hopefully also remove the firewall rules, allowing you to start again from scratch and build new rules which do not conflict with the email setup. You might also be able to find additional information specific to your security software. For example, Symantec has an article on the Outlook Express error you are receiving, which is relevant should you be running Norton Antivirus or Norton Personal Firewall: service1.symantec.com/SUPPORT/nav.nsf/docid/2001060516275506 . So, it may be worthwhile searching for such information.