We have a known issue with Facebook videos. We will email you as soon as it is resolved.
Facebook Videos Unable to download
After udating RealPlayer to version 18.104.22.1683 I get the "Unable to download" message when I try to download a Facebook video. I can download YouTube videos just fine. I have tried three browsers, Edge, Chrome and Firefox. All three fail with Facebook videos and all three work with YouTube Videos. The computer is a Win 10 64 bit.