Check out why the site is untrusted and click the "Advanced" button to expand this section to see extra details. If the certificate is not trusted because no issuer chain was provided (sec_error_unknown_issuer) then see if you can install this intermediate certificate from another source. Click the "Add Exception" button to inspect the certificate in the Certificate Viewer.

If you can't inspect the certificate via "Add Exception" then try this:

Open the "Add Security Exception" window by pasting this chrome URL in the Firefox location/address bar and check the certificate:

• chrome://pippki/content/exceptionDialog.xul

In the location field of this window type or paste the URL of the website with the https:// protocol prefix (https://xxx.xxx).

• retrieve the certificate via the "Get certificate" button
• click the "View..." button to inspect the certificate in the Certificate Viewer

You can inspect details like the issuer and the certificate chain in the Details tab of the Certificate Viewer.

I can view the certificate details, but I'm not sure what to look for that might be suspect. I've added some images to clarify but blacked out the hex addresses, fingerprints & serial numbers, since I'm not sure what's sensitive and what's not.

It seems I can add an exception. Should I go ahead and do that?

I have navigated to this modem's login page before without incident, but that was several months ago.

The certificate is issued by your modem software (Scientific Atlanta), so I think your only option is add an exception.

Thanks for your help! I suspected I would have to do that. Just wonder why I couldn't find other reports of this issue with this particular modem. I think it's a fairly common one.

Anyway, thanks again!