There are other possible locations for firewalls/network issues. You could try to connect to the given url with a regular browser. The error message indicates a network error as a failure to download that url.
Come to think of it, it used to be a problem that macosx came with some dodgy java version that in particular doesn’t support modern TLS (only supporting insecure versions). You might be able to install a recent JDK and make the problem go away.