These issues are typically caused by inconsistent security settings.  Please confirm all pages security settings are selected appropriately and functionally through the feature's Advanced tab.  If you expand the Security options, you can define the security and user access settings for the web feature.  The settings are defined as follows:

Use Web Site Default- This is determined based on the site's settings (through Administer tab>Site Settings subtab: Website Access)
Anyone can access web page- No login required
Every contact with a login in your account will be able to access web page- All users who have a username can assess the site
Membership required to access web page- Users with the selected membership on his or her contact record can access the site
Event Login required to access web page- Only contacts with event registrations for the selected Advocacy Center, CFAF, Gala, Registration Form,  Golf, or FAF event can use the site

If the security settings do not appear to be the root cause, we can create a new username.