Unable to monitor a site from Cloud Monitor due to an expired security certificate error.
When trying to monitor a site from Cloud Monitor with an HTTP monitor, you will be unable to do so if the security certificate has expired. This article explains how to work-around the problem so that you can continue to monitor a site while awaiting a new security certificate.
Move the monitor to an HTTPS type, and under advanced options review the Verify Certificate option. If the Verify Certificate option is unchecked, expired certificate errors will be ignored and you will be able to use Cloud Monitor to check site status regardless of any security certificate errors received.