This sounds like a browser issue.
For information
Chrome, Edge and Firefox are the only known browsers that work with Foundry.
A lot of Mac users have issues when trying safarai, or old windows explorer.
Make sure you’re using a compatible browser.
If they are, try using one of the others recommended above, as it might seem something is wrong.
You can follow: How to fix/turn on your browser's hardware acceleration
to see if that fixes the issue.