INVALID_TYPE error in DV joining two tables of a salesforce datasource

Issue

• Running query that joins two custom objects/tables of salesforce using primary key and foreign key throws below error:

Error: TEIID30504 Remote org.teiid.core.TeiidProcessingException: TEIID30504 MPRS_Salesforce: com.sforce.soap.partner.InvalidSObjectFault: INVALID_TYPE: 
Recipe_Step_Detail__c.Catalog_Item__c FROM Recipe_Step_Detail__cs) FROM Media_Prep_Order_Recipe_Steps__c
                                           ^
ERROR at Row:1:Column:1137
Didn't understand relationship 'Recipe_Step_Detail__cs' in FROM part of query call. If you are attempting to use a custom relationship, be sure to append the '__r' after the custom relationship name. Please reference your WSDL or the describe call for the appropriate names.
SQLState:  50000
ErrorCode: 30504