Why am I occasionally getting "incorrect username/password" when entering the correct username and password to log in?

1. Select "Tools" on the menu bar of Internet Explorer
2. Select "Internet Options"
3. Select the "Security" tab
4. Select the "Trusted sites" zone
5. Click on the "Sites..." button
6. Make certain the box is not checked for "Require server verification (https:) for all sites in this zone"
7. Enter https://cc.ivytech.edu as the zone to be added
8. Click the "Add" button
9. Click OK
10. Click OK again