Hello! I've been having an issue ever since I downloaded firefox for my Mac where, no matter what the streaming service, I cant stream in full HD, 1080p quality. My monitor can display Full HD, and I just bought a 4K HDMI cable to try and fix this issue. Didn't work. I did download Crome to see if anything can help, but that had the same quality problem. However, it DOES stream Full HD on Safari, but I much prefer firefox.

Any help is greatly appreciated!