Ways to fix this error- Install a better browser with Twitch integration. Temporarily turn off VPN Troubleshoot the network connection. Refresh the stream. Clear the browser's cache. Disable extensions. Try the desktop client. Temporally disable your third-party antivirus.

Greeting, Rachel Gomez

Ways to fix this error- Install a better browser with Twitch integration. Temporarily turn off VPN Troubleshoot the network connection. Refresh the stream. Clear the browser's cache. Disable extensions. Try the desktop client. Temporally disable your third-party antivirus. Greeting, Rachel Gomez

At the time i wasn't running a VPN, i tried refreshing stream and clearing browser's cache, as i said i ran firefox on troubleshoot mode (that means extensions and custom settings disabled), i'm having this issue on desktop not on mobile, and for sure it isn't a network problem because it works perfectly on Google Chrome and other browsers

Have you encountered issues playing video on any other sites?

I don't know what format that video used. If you open Firefox's web console (Ctrl+Shift+K) perhaps there will be an error message or warning about a specific CODEC or other useful lead. Hopefully.

I also am having this problem with only 1 streamer I watch, everyone else I checked is fine. Some other searching said this is caused by the streamer using 7.1 channel audio, which the streamer I have this problem with confirmed they were using and they will update for the next stream to see if that fixes it.

This is the error in console: Media resource blob:https://www.twitch.tv/29a3f195-45bd-4459-9f87-8ab5d6de37fe could not be decoded, error: Error Code: NS_ERROR_DOM_MEDIA_FATAL_ERR (0x806e0005) Details: Error creating decoder for audio/mp4a-latm

Should be noted I'm running the Waterfox branch which is only version 102.0 based but it appears to be an issue with Firefox as seen by OP and some other people having this problem.