Hi, thanks for sharing this issue.
The exception you've described isn't originating from NCrunch - this is coming from either your test code or your code under test. NCrunch communicates over its grid directly using TCP streams, where this exception seems to be HTTPS related.
Without knowledge of your code, unfortunately it isn't possible for me to provide you with a solution to this problem. However, looking at this error, I would speculate that the remote grid server responsible for running the test needs to have an SSL certificate installed on it in order to run your application.
Is it possible that the remote grid server is missing some key piece of configuration necessary for the execution of your code?