If you head over to Bing.com using SSL, you will notice a security certificate error. Users can still proceed to view Bing.com but this error is obviously something that shouldn't be present.
Heading over to https://bing.com will result in a SSL error which tells you that you are most likely visiting a malicious website. "An attacker on your network could be trying to get you to visit a fake (and potentially harmful) version of bing.com. You should not proceed, especially if you have never seen this warning before for this site," Google's Chrome browser warns.
Typically, HTTPS is used to encrypt communication so malicious eyes cant see network activity to see what users are searching for. In order for this to work, there needs to be valid and updated security certificates. Looks like Microsoft dropped the ball on this one. Microsoft has yet to release an official statement on the matter or an explanation.
Microsoft's Azure cloud-based computing platform experienced an outage back in February 22nd, which was a result of an expired SSL certificate. As a result, services were either offline or suffered from poor performance due to the expiration.
Update: It appears that the certificate issue has been resolved. Microsoft is using Akamai for the certificate service, where the problem had originated from."We're working with Akamai on that. It should be fixed soon," Microsoft had stated before the issue was eventually resolved.