sometimes the thumbnails with video content won't show up and also the rest of the site, that is not visible in the viewport (maybe every 3th-5th time I'm loading the page, just keep refreshing to see it). Links are not clickable, it seems the site is frozen for about 10 sec. It occurs on Safari 4.0 on Mac OSX 10.15.6. I have no clue what's wrong, maybe you can help me with that. Screenshot of the site with error attached.
link to site: https://www.felixfinger.de