Case

Pyramid 2018 is installed on domain A, and you want to add a tabular server that is running on a server with no domain

 Solution

Usually, this would break the security model of how analysis services work. In that users from Pyramid installed in domain A, would not be recognized when trying to login to the tabular server installed on a server that is not on a domain.
However, if required, it is possible to workaround using the following steps:

1. Install the Pyramid Windows Connector service (DNC.exe) on the Tabular server.
   Then delete the PWC which was installed by default on the Pyramid 2018 server from the Admin>settings>server instances.
    
2. If you are using AD authentication, you will need to go to the Pyramid 2018 repository and delete the contents of the column 'principal_name' in the user's table, for the user you wish to connect with to the data source.

The issues with the above is that:

1. You will not be able to connect to any other Tabular/Analysis services that are not on the same server as where the DNC service is installed on.
    
2. For the user that you deleted the value in the column 'principal_name', you will not have cube security per user.
   I.e. Pyramid 2018 will connect with the user that was set up in the admin for that data source.
   A workaround for this would be that each user will add it's own data source using his a username that exists where the DNC is installed.