I recently moved to a new Windows machine and can not send mail from either hotmail or gmail accounts. I am able to send and receive from my account at outlook.office.com, but hotmail uses outlook.office365.com as the mail server. '''Thunderbird Version: 115.10.0 Windows 11 Version: 23H2''' The message I receive when trying to send is: ''Sending of the message failed peer's certificate has an invalid signature the configuration related to smtp.gmail.com must be corrected '' (also for smtp.office365.com) I did try all of the fixes advised here, as the error message certainly matched what I was seeing: https://support.mozilla.org/en-US/questions/1295861 so my settings in TB are currently: ''security.tls.version.min = 1 security.tls.version.enable-deprecated = true'' The final suggestion in the above thread was to move back to Thunderbird version 68.11.0, which I will try if nothing comes of this thread by the weekend.