Problem: Server unexpectedly terminated the connection

Solution:
1. Click on Tools
2. Click on Accounts
3. Click on Properties
4. Click on Advanced (up on the top)
5. Move the slider for Server Timeouts to the right.

Solution for Outlook Express :
1. Click on Tools
2. Click on Accounts
3. Highlight your mail account by clicking on it.
3. Click on Properties
4. Click on the Advanced tab up on the top.
5. Move the slider for Server Timeouts to the right.