The configured digital certificate is not valid for RDP files, or the certificate is not installed on this computer. To digitally ...

The configured digital certificate is not valid for RDP files, or the certificate is not installed on this computer. To digitally sign an RDP file, you must select a different certificate. If you do so, all listed RemoteApp programs and the remote desktop connection will be signed with the new certificate.  If you do not select a different certificate, all new and existing RDP files will be generated without a digital signature. Depending on Group Policy settings, this may prevent users from connecting to the terminal server.  Would you like to select a different certificate?