Error while trying to access datasource

In the admin console, the connection is successful for the datasource. When I try to create a CDT from database by selecting the newly created datasorce, I am getting below error:

Error Evaluating UI Expression Expression evaluation error : [valid:false,syntaxError:false,value:Expression evaluation error: An error occurred while executing a save: Expression evaluation error at function fn!getSchemaNames_appian_internal(_) [line 78]: com.microsoft.sqlserver.jdbc.SQLServerException: The SELECT permission was denied on the object 'schemas', database 'mssqlsystemresource', schema 'sys'.]

Thanks,

Varsha