I needed to reinstall Firefox on this computer, so I started up Chrome to download the latest version and it blocked the download as unsafe! I had to manually tell it to download anyway.
Fuck Chrome. I’m glad I only used it to download one file and went back to Firefox.
Your safe browsing was disabled, as another commenter said. Either you had it disabled manually, or it was momentarily down and couldn’t fetch the list. Either way, it marks all downloads as unsafe just to be sure in that case.