If you are trying to watch a live stream from Arcus on a Mac computer using Safari, you will need to be sure that the Adobe Flash browser plugin is updated and activated in the browser. Each time Safari updates, however, you may need to repeat this process. Here are the steps to do this:
1. Open the Preferences menu in your Safari browser.
2. Click on the Extensions tab.
3. Select the Adobe Flash Player extension (if you don't have it, you will have to install it from Adobe's website here: https://get.adobe.com/flashplayer/otherversions/).
4. Make sure the setting for "Web visiting other websites" is set to "On".