Event ID 15021 HttpEvent on a wildcard SSL certificate but only get the error on a couple sites

I have IIS running on Windows Server 2012 R2. I have a wildcard SSL certificate on 14 subdomains. I’m seeing a lot of errors in the Event Viewer.

Event ID: 15021 Source: HttpEvent

An error occurred while using SSL configuration for endpoint my.domain.com:443. The error status code is contained within the returned data.

However, I’m only getting this error on 2 of the sites, the other 12 are not logging this error. The 2 sites creating this error load up fine in a web browser. I’ve checked the binding in IIS and they both have the wildcard SSL selected.

If there is a certificate problem, I would expect this error coming from all 14 sites, not just 2 of them.

Though those 2 sites load fine in a browser, I’m not comfortable seeing thousands of these errors on our two biggest sites.