Gateway exposes services via HTTP, therefore the Gateway services must be activated on the NetWeaver ABAP system. As HTTP services are run by ICF, they are controlled by transaction SICF. The services to be activated for Gateway system that d not care about compatibility mode for SP02 are

• /sap/public/opu
  
• /sap/opu/odata

More information: SAP Help

These services are activated by activating the corresponding node and all sub elements.

Sap/public/opu

1. Go to transaction SICF
2. Execute and navigate to sap/public/opu

   

3. Select Activate Service
4. Select Yes

   

5. Node is activated

   

/sap/opu/odata

1. Go to transaction SICF

   

2. Execute and navigate to sap/opu

   

3. Select Activate Service
4. Select Yes

   

5. Node is activated

   

6. Make sure that the handler for /sap/opu/odata is /IWFND/CL_SODATA_HTTP_HANDLER