I recently found a bug in the December 2011 Release of EWSEditor and just checked in and released an updated build to EWSEditor to fix it.  Here are my bug notes from the check in:

“…Bug in ValidationCallbackHelper.CertificateValidationCallBack caused certificate validation to fail always - unless the override validation setting was turned on. Instead, ValidationCallbackHelper.CertificateValidationCallBack now looks for SSL policy errors and returns true if there are none. If there are errors and override is not set then it will return false and output the error code in the debug log…”

You’ll notice that the build’s revision number is actually lower than the previous December 2011 release – please ignore that, is the latest release.  This should be fixed going forward, sorry for the confusion.