Taz, I fixed my problem. I'm using Chrome, version 87. To make a long story short, once I allowed third-party cookies on Facebook site, the HTML5 version loaded perfectly. One can find this under settings, cookies. Or, when in Facebook, check the address bar and to the far right you will see an eye icon. Click on that and click to allow third-party cookies. This solved my loading problem and hop it helps someone else.
Kathy
