Vamos a realizar la traducción pero por el momento pueden usar estas instrucciones en inglés:

If you are trying to send email using SMTP while using an antivirus program such as Norton, your SMTP connection may be timing out while your antivirus program takes time to scan each outgoing message.

To adjust the timeout setting in your POP client, please follow these instructions:

Outlook 2000 (CW)
1. Start Outlook.
2. On the Tools menu, click Services.
3. On the Services tab, select Internet E-mail, and then click Properties.
4. Click the Advanced tab.
5. Gradually increase the server timeout setting until the problem is resolved.

Outlook 2000 (IMO)
1. Start Outlook.
2. On the Tools menu, click Accounts.
3. Select the target account, and then click Properties.
4. Click the Advanced tab.
5. Gradually increase the server timeout setting until the problem is resolved.

Outlook 2002 and Outlook 2003
1. Start Outlook.
2. On the Tools menu, click E-mail Accounts.
3. Click View or change existing e-mail accounts, and then click Next.
4. Click your POP3 account, and then click Change.
5. Click More Settings.
6. Click the Advanced tab.
7. Gradually increase the server timeout setting until the issue is resolved.

Outlook Express 5.x and 6.0
1. Start Outlook Express.
2. On the Tools menu, click Accounts.
3. Click the Mail tab.
4. Click your POP3 account, and then click Properties.
5. Click the Advanced tab.
6. Gradually increase the server timeout setting until the problem is resolved

If adjusting the timeout in your POP client does not resolve the issue, then turn off email scanning (your computer will still be protected but mail going out will not be scanned).

If you are not using an antivirus program, check to ensure that if you are behind a firewall or router that these devices are not interfering with your mail activities.