"An error occurred while calling service. Exception has been thrown by the target of an invocation. The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. The remote certificate is invalid according to the validation procedure."
Go to your SharePoint site web.config (default location C:\inetpub\wwwroot\wss\VirtualDirectories\<<port>>) on which Winshuttle is configured and add the following line within system.net tag on all web front end servers:
<servicePointManager checkCertificateName=”false” checkCertificateRevocationList=”false” />