macOS Sierra to macOS Catalina

I have macOS sierra and I'm trying to download macOS Catalina, but It won't let me, i have no adblocker or malware (I have the macbook air 2017). When I click the apple logo and go to about this Mac and software updates, it redirects me to the App Store. There I tried downloading macOS Catalina, it downloads and then disappears, when I go back to the App Store it says I can download it again. I've been trying this for hours. No pop-ups show up. I have enough storage space, so I don't think thats the issue. Someone please help me:(