The SSL client certificate for jcuriel will expire on 20190911. Please work with them to get the new certificate issued and installed.
Had some issues with this working one day and then not the next. It ends up that Jonathan had imported the cert into the OS keychain but not into firefox also. Firefox requires the cert to be imported specifically. The behavior looked like it was working and then failed because firefox was still using the old certificate until it expired. Additionally, the browser needed to be quit and restarted as it cached the certificate it was using for the connection.
I walked through his config with him and cleared out all old/expired certs and ensured his new cert was working. I'll see if there is anything we can clarify in the documentation so this doesn't trip up other users.