Just because you can access the site doesn't mean it doesn't have a bad certificate. Browsers usually just ask if they can go ahead anyway, and they'll often mark the exception as permanent, so they'll never ask again and you'll forget it happened.
Your browser should have an option to examine the certificates of sites you've visited. Check the certificate there.
An IDE is no substitute for an Intelligent Developer.
Die Fledermaus does not fear such a tiny ad:
Thread Boost - a very different sort of advertising