After more than 15 years covering everything Apple, it’s with a heavy heart we announce that we will no longer be publishing new content on iMore and the iMore forums will be closing as of November 1st, 2024.
Check Safari / Preferences - Extensions. Make sure you don't have an Extension installed that may be preventing Flash to stream video. Also, if you have antivirus software installed, try disabling that then restart your Mac. I came across the situation the other day where a user had Virus Barrier installed and couldn't stream Flash content. Once they adjusted a setting in their VB preferences, they were able to view videos.