This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Secure connection failed start.thunderbird.net uses an invalid security certificate. The certificate is not trusted because the issuer certificate has expired.

  • 3 replies
  • 2 have this problem
  • 1 view
  • Last reply by Stans

more options

I get this message: Secure connection failed




         start.thunderbird.net uses an invalid security certificate.

The certificate is not trusted because the issuer certificate has expired.

(Error code: sec_error_expired_issuer_certificate)

How do I fix it? Thanks, Susie

I get this message: Secure connection failed start.thunderbird.net uses an invalid security certificate. The certificate is not trusted because the issuer certificate has expired. (Error code: sec_error_expired_issuer_certificate) How do I fix it? Thanks, Susie

All Replies (3)

more options

This tends to happen when you've decided to stick to old outdated unpatched versions of software. You're running Windows 7, browsing using Firefox 52 and I'm guessing your version of Thunderbird is just as old, isn't it?

more options

I have this problem too -

Secure connection failed

start.thunderbird.net 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…

When I click on add an exception nothing happens. I tried closing Thunderbird, deleting my cert8.db file and restarting Thunderbird - no change - same message. I am running Windows 10, Thunderbird version 45.4.0 Help, please ! Thanks, Sarah

more options

Update your version of Thunderbird.