Cannot open certificate store on the machine
First off, launch SSMS on the SQL Server instance you intend to be the master. The steps to troubleshoot start with the two steps here:
"1. Run Scale Out Manager as administrator. If you open Scale Out Manager with SSMS, you have to run SSMS as administrator.
2. Start the Remote Registry service on the computer if it is not running."3. Finally, if you are trying to add a named instance, there is one more gotcha. The Scaleout Worker is the server name not the SQL Instance name. Do not provide the full named instance name, for example, "SQLSERVER-1\INSTANCENAME", only provide the server name, in this case, "SQLSERVER-1".