Hello and thanks for your attention. I have problem with Firefox and Thunderbird after new Windows 10 installation. I receive "Authentication Required" window, one with "User password Manager to remember this password" checkbox and one without it. I enter my username and password and make sure checkbox is checked. Proxy works perfectly but after program reload i receive authentication windows with empty username and password inputs. I solved this problem in Firefox with FoxyProxy extension but I can't solve it in Thunderbird. I also have KeePassXC. Tried to delete it but this doesn't help. Windows 10 version - 21H1 (19043.1165) Firefox version - 92.0 Thunderbird version - 91.1.0