I can't unblock Java in Firefox/Windows 7

There’s a cryptogram game I really love that I haven’t played for awhile. I finally found its website after a long absence, and I keep getting a window that says, “Your security settings have blocked an untrusted application from running.”

I went to the Firefox page dealig with how to enable Java, but nothing has worked. Oddly enough, the “appliation blocked” window has an icon of a lower-case “i,” which I associate with Internet Explorer

I am confused. Help!
P.S. Should have mentioned that the game needs a Java applet to run.

You may have to uninstall and re-install Firefox. I have had to do that in the past.

Here’s an answer elsewhere.
https://support.mozilla.org/en-US/questions/983382

One response is:
This message isn’t coming from firefox but from the java plugin - please refer to oracle’s documentation:
http://www.java.com/en/download/help/appsecuritydialogs.xml

It’s not a Firefox problem. You have to go to the security tab in the “Java Control Panel” and either lower your security settings or add the site to the exception list. It’s in my start menu as “Configure Java.”

If you’re going to lower Java’s security settings, you had better make damned sure you’ve at least got the latest updates, and that you keep it up to date continuously. Really, I’d recommend only lowering the security settings when you’re gonna play your game, then put it back like it was. And if you stop playing the game for a while, uninstall Java until you need it again.

It would seem the best solution would be to add the specific site to the exception list.