Error M Code: Missing Module Reference

[JaromG]

I want to get a distinct list of clients. (Steps Source Through ListOfClientKeys){

Then I want to pass that list into an analysis service query (Step "Client")

Revenue Details is another table in my model that processes fine. It has a column called Client Key.  

I am receiving this error:

<ccon>The import Revenue Details matches no exports. Did you miss a module reference?</ccon>

Please help me figure out how to resolve this error! Kind regards. 

let
    Source = #"Revenue Details"[Client Key],
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Client Key", type text}}),
    ClientKey = #"Changed Type"[Client Key],
    ListOfClientKeys = Text.Combine(ClientKey,","),

    Clients = AnalysisServices.Database(SSASServer, "tabularModel", [Query=
                    "DEFINE

                    VAR _ClientKeysInSnapshot =
                        TREATAS ( {"& ListOfClientKeys &"}, D_Client[ClientKey])
                        
                    VAR _FinalProduct = 
                    SummarizeColumns(D_Client[Global Client Name],
                        D_Client[ClientID],
                        D_Client[ClientKey],
                        D_Client[ClientName],
                        D_Client[Global Management Niche],
                        _ClientKeysInSnapshot)
                
                EVALUATE
                _FinalProduct", Implementation="2.0", CommandTimeout=#duration(0, 0, 120, 0)]),
    #"Renamed Columns" = Table.RenameColumns(Clients,{{"D_Client[Global Client Name]", "Global Client Name"}, {"D_Client[ClientID]", "Client ID"}, {"D_Client[ClientKey]", "Client Key"}, {"D_Client[ClientName]", "Client Name"}, {"D_Client[Global Management Niche]", "Global Management Niche"}}),
    #"Filtered Rows" = Table.SelectRows(#"Renamed Columns", each not Text.StartsWith([Client ID], "OAM.NT") and not Text.EndsWith([Client ID], "-HF"))
in
    #"Filtered Rows"

[lbendlin]

As the message says - you use "Revenue Details" without specifying what data source sits behind that. Power Query cannot infer that you want to pull this data from a cube. You have to use the same AnalysisServices.Database connector as you do later on for your DAX query.