This is a common error and does not mean anything is wrong or broken. This message simply means that the certificate is not signed by an SSL Certificate Issuer. Therefore if an SSL Certificate is self-signed this error might show. To get around this error, follow the simple instructions below:
Step 1: Click the "I Understand the Risks" text
Step 2: Click the "Add Exception" button
Step 3: Click the "Get Certificate" button.
Step 4: Click the "Confirm Security Exception" button.
Step 5: That's it! The page should now load just fine. If the error ever shows again, just follow these steps.