빠른 여우가 게으른 개를 뛰어 나머요.
빠른 갈색의 여우가 …
You don't need to write 갈색의, just 갈색 is okay and sounds natural.
How is The lazy dog eats slowly different?
Present progressive vs. Present simple
How is "the lazy dog eats slowly incorrect?"
it's 18/11/2021 now and it's still incorrect
The lazy dog eats slowly
Why not ' the lazy dog eats slowly?
the lazy dog slowly is eating
although it's a bit awkward, should be accepted
I don't think your English grammer is correct on that one. Maybe that's why it wasn't accepted :)