Make sure that the name of the table is specified in the URL. For example, if the DSN is SQLServerTest and the table is Customers, then specify:
Also make sure that the name of the OData entity that maps to the table and the case of the entity name match. For example, suppose the name of the table is Customer in the database: in the OData model the name that is exposed is pluralized so the name becomes Customers.
To see the name of the entities exposed by the OData service, submit a GET request to the root URL for the service in a browser or in a REST tool such as Postman:
In the response, the correct table name is specified: