Looking for logging into the Firefox Sign In site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Firefox Sign In site. After that you can login as usual with your login credentials.
https://support.mozilla.org/users/login
https://www.mozilla.org/ja/firefox/accounts/
https://support.mozilla.org/ja/kb/access-mozilla-services-firefox-accounts
https://support.mozilla.org/ja/kb/how-do-i-set-sync-my-computer
https://addons.mozilla.org/firefox/users/login
https://support.mozilla.org/en-US/kb/access-mozilla-services-firefox-account
https://support.mozilla.org/ja/kb/how-do-i-delete-my-firefox-account
https://support.mozilla.org/ja/kb/access-your-add-ons-firefox-accounts
https://addons.mozilla.org/ja/firefox/users/login
https://support.mozilla.org/en-US/kb/sync-bookmarks-tabs-history-and-passwords-android
https://addons.mozilla.org/ja/firefox/addon/access-panel-extension/
https://support.mozilla.org/ja/kb/add-on-signing-in-firefox
https://support.mozilla.org/en-US/kb/sign-pocket-your-firefox-account