Mozilla Company decision instructions , resulting in the inability to open Twitter in Firefox (an error or a blank page is shown). The problem has been manifest since Firefox 81, but affects only a subset of users.
As a workaround for reactivating the ability to open Twitter, it is recommended to find the "Origin: https://twitter.com" block on the "about:serviceworkers" page and disable it by clicking the "Unregister" button. Disabling ServiceWorkers support by deactivating the dom.serviceWorkers.enabled parameter in about:config also solves the problem. In some cases, but not in all, reloading the page with clearing the cache (Ctrl + Shift + R) helps.
Source: opennet.ru