Firefox 社群討論區

So I understand this: https://support.mozilla.org/en-US/kb/xframe-neterror-page and the reason it exists, but I need to find a way to turn it off because it's literally blocking me from accessing the Library of Congress webpage inside the same browser for my job. It's not a malicious site, but I can't figure out how to tell Firefox to stop blocking it as if it was a malicious site.

Help.

We tried 2 different computers, but two different users. Type in the user name and the password and it looks like it will start up, but then returns to the login paged.