Yes, that's quite strange. Please check the current e-mail settings on both your computer and iPhone.
On your computer:
1. Start Windows Live Mail
2. On the left, locate your e-mail account, right-click it and select Properties
3. Click on the Servers tab
Let me know what it says for the Outgoing mail (SMTP) box. Also, let me know if the "My server requires authentication" check-box on the bottom is checked?
On your iPhone:
1. Go to the home screen and tap on Settings
2. Scroll to select Mail, Contacts, Calendars
3. Tap on your e-mail account
4. Tap on your e-mail address on the top
Let me know what it says for SMTP located in the OUTGOING MAIL SERVER section?