Quote:If you run Firefox Nightly on your devices you may have noticed that updates don't get downloaded and installed anymore. Firefox Nightly displays the update notification in its interface but downloads don't happen anymore and Firefox Nightly will display update notifications in a loop regularly while the browser is being used.

Firefox notifies users about updates; the small overlay gives users options to start the update process. The process is broken in Nightly, however.

Firefox Nightly displays the "A new Nightly update is available" notification on start. Activation of "Download Update" has no effect in affected versions of Firefox Nightly.

Firefox users who check for updates manually in the browser, by opening Menu > Firefox > About Firefox, are notified on the "about" page that an update is available. Activation of the update to button does nothing, however.

Mozilla is aware of the bug; it is filled under 1517718 on Bugzilla: Firefox Nightly gets an infinite spinner when checking for updates.

Full reading: https://www.ghacks.net/2019/01/08/the-firefox-nightly-updater-is-broken-right-now-do-this-to-fix/