In SP 2013 we have an Infopath form that calls the UserProfile webservice. The web application is https. We keep getting the certificate validation issue intermittently (normally on first load or after the page has been idle). The Development dashboard shows that SPCertificateValidator.Validate sometimes takes 32 sec (limit is 15) but sometimes it just takes 7 seconds.
I have already imported the SP Root Authority in the Trusted Root CA as described here and also imported the SSL certificate and WorkflowOutbound certificates.
I have also disabled CRL checking over the internet.
What am I missing?