Prompted for Safari login

I cannot login to Safari at my school. I am prompted for username and password. Why is this happening?

Your computer is either not within the authorized IP address or you may need to restart your computer's browser to login. If the computer in question is within the authorized IP range, it is possible that a previous user used the log out button. Try closing all browser windows, opening a new browser session, and logging back into Safari.

If the problem persists, use this URL, http://safari.bvdep.com/bo/ShowIP.asp, and return all information contained to ProQuest. We will follow up with the subscribing institution to ensure that the account is set up correctly.  We will contact you when the issue is resolved so you can attempt the login again.