ISPs that use proprietary versions of browsers, such as AOL or Prodigy, can cause some problems for EZproxy. A simple workaround is to connect to the provider, minimize your AOL session and use your own copy (you can download it) of Internet Explorer or Netscape for accessing the library's resources instead of AOL's or Prodigy's proprietary versions of the browser.
Another common problem is that during initial set up of dial-up, cable, or broadband connections, certain browser settings get configured according to AOL's or Prodigy's own preferences, rather than the settings you need for EZproxy. That is yet another reason to minimize your AOL or Prodigy session and instead use your own copy of Netscape or Internet Explorer when accessing library resources.