I'm facing the same issue as well, so let me add a few more details.
I believe both Evan and I have a free OpenShift plan, which provides a shared SSL certificate for *.rhcloud.com. They do allow custom DNS CNAME records so that you can map your own domain to your OpenShift site, which is of the form appname-namespacename.rhcloud.com. I think both of us have mapped our own domains to our OpenShift websites, and hence the SSL certificate error.
Is there any possible workaround for this? OpenShift is amazing for small to midsize-blog owners like us.