DeepL is a good translator. Ever since their founder left Google and started DeepL it gave better results than its parent. During its development period DeepL worked with the community and offered great results of top notch quality. But at some point the bills need to be paid. And things were/ are locked down, put behind walls (thank you for your cooperation). This extension is no exception. It promises the excellence of DeepL... but then it never delivers. It just doesn't work with many FF configurations, often not due to your config, but because of their pressing quest to make you a paying customer. And then alternatives, that do work, become much better in that comparison, despite your superiority. But then again, maybe they just don't need us plebs (any more)...