#Firefox download addon install

I enabled 'allow site to install add-ons' and 'allow pop-ups', etc.My Mac is connected to a secure university wi-fi.I probably have tried other methods along the way but cannot recall anything significant.I obtained several other URLs by inspecting buttons of other add-ons and got the same 404 result, regardless of the browser. I tried opening the link in other browsers (chrome, safari) and got the same result, which is super weird. Interestingly, when I click on the firefox download link at adblockplus website, it comes back with GET requests were responded with 404 as well. Accessed the aforementioned link directly.I got this URL by inspecting the 'Add to Firefox' button in the webpage (still getting 'Download failed. I tried InstallTrigger.install() in the console.xpi file directly using other browsers, but when I tried to add it manually, the following showed up Added 'xpinstall.enabled => true' and ' => false' in about:config (doesn't do anything).I don't have any antivirus software in my Mac, at least not that I know of.I duckduckgo-ed this issue and tried all the following solutions: What I've done trying to solve this issue I checked the console and it seems that the GET request was responded with 404. For instance,ДЄs you may see in the screenshot, images in this site cannot load properly as well. It seems that no add-ons coming from can be installed, all due to the same issue ('Download failed. New to firefox, I tried to install some cool add-ons but failed to install any except for one ( zotero).

Firefox download addon