When I launch Thunderbird I get the following 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 Thunderbird then automatically downloads emails without asking me for a password. I have just migrated to a new desktop computer (MSI CUBI 5) and this started immediately. When I try to send email I get a message telling me my outgoing server does not have a certificate, but this doesn't appear to be Thunderbird's problem? I'm not happy about any of this? Can you advise me please where I should be directing my request for help? It doesn't seem like it should be a Thunderbird issue, but the address includes the word mozilla so I am sending it to you... Thanks for any help you can offer, I really like (and support) your software. Margaret