Last Saturday morning on Nov. 19th I downloaded to Thunderbird from my Hotmail account then later that day I went to get messages and received the following message: Sending of password for user [email protected] did not succeed. Mail server pop-mail.outlook.com responded: Authentication failure: unknown user name or bad password. [Error="AuthFailed:LogonDenied-FederatedStsUnreachable-<X-forwarded-for:71.237.197.120><ADFS-Business-114ms>failed logon error - STSFailure - '<S:Fault xmlns:S='http://www.w3.org/2003/05/soap-envelope'><S:Code><S:Value>S:Sender</S:Value><S:Subcode><S:Value>wst:InvalidRequest</S:Value></S:Subcode></S:Code><S:Reason><S:Text xml:lang='en-US'>Invalid Request</S:Text></S:Reason><S:Detail><psf:error xmlns:psf='http://schemas.microsoft.com/Passport/] I made no changes to Thunderbird's settings or my password. I checked my saved passwords in Thunderbird and they were correct. I have no problem sending out email from [email protected] but I cannot receive or download the emails. The account settings are: email address: [email protected] Server Type Pop Mail Server Server Name; Pop-mail.outlook.com UserName: [email protected] Outgoing Server (SMTP) Settings: Outlook.com (Microsoft) - smtp-mail.outlook.com