In case it helps to figure the problem or anything , I'm personally not having any issues , all seem to be fixed and I'm downloading the courses just fine right now . (Using Windows 10 x64) .
Would you try it?
https://www.udemy.com/behzat-rasuli-karmasik-sayilar/thanks.
Yes of course , here is the results (negative results) :

Personally my courses wasn't password protected , so I guess this is the reason since your it's password protected .