This could be a problem with the server's configuration, or it could be someone trying to impersonate the server.
   If you have connected to this server successfully in the past, the error may be temporary, and you can try again later.

Dear Sir or Madam, I have just migrated Thunderbird to my new CUBI desktop running Windows 11. I get security errors when I launch Thunderbird. My email provider The Messaging Company advised me to change server settings, which are now shown in the Troubleshooting Information page as account1 (pop3) pop.themessagingco.com.au:995 SSL/TLS Normal password smtp.themessagingco.com.au:587 STARTTLS Normal password true. On launching Thunderbird I get the message Secure connection failed live.mozillamessaging.com uses an invalid security certificate. The certificate is not trusted because the issuer certificate has expired. Error code: <a id="errorCode" title="SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE">SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE</a> This could be a problem with the server's configuration, or it could be someone trying to impersonate the server. If you have connected to this server successfully in the past, the error may be temporary, and you can try again later. Or you can add an exception… AND when I attempt to send an email I get warning that the SMTP server does not have a valid certificate. If I ask, in either case, to "Get Certificate" the response is that the site attempts to identify itself with invalid information. I have "tried again later" over two weeks, and nothing has changed. The Messaging Company is a fairly large email provider: it seems strange that its security is incomplete. However, I am not happy to just set an exception and over-ride these errors without doing all I can to check that there is not something screwy going on. I really value using Thunderbird, and The Messaging Company's advice that I should just use webmail is not at all satisfactory: I keep everything on my computer or backed up to a portable drive here. Please: is there anything I can do or should know to fix this problem? Best Regards, Margaret Mackisack