i am trying to access navy knowledge online, but whenever i get to the website it says

"This Connection is Untrusted
You have asked Firefox to connect
securely to wwwa.nko.navy.mil, but we can't confirm that your connection is secure.
Normally, when you try to connect securely,
sites will present trusted identification to prove that you are
going to the right place. However, this site's identity can't be verified."

how can i bypass or disable this setting?