So i was able to successfully download unity 2019.3.5f1 but whenever i try to download other versions itll download, but when it finishes it’ll just dissapear. it doesnt show any errors or anything. it just acts as if i never downloaded it. i’ve tried multiple versions and they all do the same. Ive also tried downloading it straight from the site and not Unity Hub.
The easiest way is probably to use Unity Hub. That handles all these problems for you.
But if you don’t want/can use it… On what OS are you?