For end-users:
- Check with your registrar and make sure that the domain name hasn’t expired.
- Make sure that your email inbox and/or domain didn’t exceed its quota.
- Use your full email address as username (i.e., username@domain.com).
- Switch to a different port such as: 26 or 1000 for SMTP Outgoing Server .
- Login to your control panel and remove any mail filter you have.
If you can’t send and/or receive using MS Outlook/Outlook Express do the following:
- Make sure that “My Server Requires Authentication” is checked in your Outlook/Outlook Express.
- Make sure your Anti-Virus and/or Windows firewall are not blocking you from sending/receiving email
- Go to your DOS prompt and issue the following command: ipconfig /flushdns
- Run Windows Disk Defragmenter and wait until it is completed.
- Power off, wait for a few seconds, and then power on your PC.
- Turn off any firewall you might have on your own PC, including Norton and McAfee.