Mozilla released Firefox 81.0.2 today, October 13th, 2020, to the Stable desktop channel for Windows, MacOS, Linux, and Android. The issue affecting a large number of Firefox users caused the web browser to display blank pages or errors instead of loading Twitter pages on both desktop and mobile devices. Mozilla didn’t share the Firefox versions impacted by this problem, users said that the Twitter loading errors started to appear after updating to the Firefox version last month. If you can’t immediately update to version 81.2, you can work around the errors showing up when trying to open Twitter.
Source: https://www.bleepingcomputer.com/news/software/mozilla-releases-firefox-8102-to-fix-twitter-errors/