Cant download of garrysmod.org

I have recently had problems with gmod.org becuase when i try to download something or try to log into my steam account my web browser (firefox) will just load up a with screen and will not start the download or anything.
i have downloaded gmod leagaly. This started a couple of weeks ago. I have checked on a website and it said that gmod.org was down but when i enter it into my address bar it loads fine? If you can help that would be great

Garrysmod.org is only usable by children over 5 years of age. If you’re under 5 years old, a Justin Bieber avatar is created by default for you so as to match your voice.

Try posting in the garrysmod.org subforum next time.

You need to buy the game first