WAC giving : Couldn't get the PowerShell language mode of this computer

Hi SIDFVAN,

It appears that the issue might be related to insufficient permissions that the user in the local group "Windows Admin Center Administrators" has. Even though the user is part of the local group, they may not have the necessary permissions to perform certain operations that require elevated privileges, such as accessing PowerShell on the remote server.

You need to confirm that the user in question has the necessary permissions within Active Directory and the role-based access control (RBAC) settings in Windows Admin Center. Secondly, check the PowerShell execution policy and Group Policy settings to ensure they don't restrict the user's access (Get-ExecutionPolicy). Lastly, attempt a manual execution of a PowerShell command on the remote server to investigate if the issue is specific to Windows Admin Center or a broader problem with PowerShell remoting.

Hope this helps!