Mozilla has shared info on how to fix a known issue leading to errors on multiple video streaming platforms including Netflix, Hulu, Disney+ and Amazon’s Prime Video on the Mac version of Firefox 84. Users advised installing Rosetta on their Apple Silicon Macs as a quick fix. Rosetta 2 is required on Macs with Apple Silicon to run apps built for Macs an Intel processor. Users are not asked to install Rosetta in order to open Firefox, which is the default behavior when launching an Intel dedicated app.
Source: https://www.bleepingcomputer.com/news/technology/mozilla-shares-fix-for-netflix-hulu-errors-on-apple-silicon-macs/