Unable to install Roblox on Mac due to download failure

I can't seem to download roblox on my mac. I can download the file but when it says double click to install and I do, a settings icon pops up and says download failed and to check my internet but I've been trying to download for a month already and the same message keeps popping up

[Re-Titled by Moderator]

Original Title: Downloading Roblox