Assistance Required in Connecting to SAP S/4HANA OData Service via External Clients (Postman / Appli

[ChrisJustus]

Dear SAP Support Team,

I am currently working on establishing an external connection to our SAP S/4HANA system using OData APIs, as part of an application integration requirement.

I have already identified the OData service endpoint using the SAP transaction/n/IWFND/MAINT_SERVICEand successfully activated the service. The OData service functions correctly from within the SAP Logon / SAP GUI environment, confirming that the service itself is active and reachable from the internal SAP side.

However, I am facing difficulties when attempting to access the same OData endpoint using Postman (and subsequently from my application). The connection attempt either times out or fails to find the host.

Below are the current details and findings:

Details:

• SAP System Type: S/4HANA

• Service Activation: Done via /IWFND/MAINT_SERVICE

• Service Status: Active and working when accessed within SAP GUI

• OData URL (sample):
  https://<host>:<port>/sap/opu/odata/sap/<SERVICE_NAME>/

• Authentication Types I want to test:

  • Basic Authentication (username/password)

  • OAuth 2.0

• Observed Behaviour:

  • Works inside SAP LOGON

  • Fails when accessed externally via Postman — results in connection timeout or authentication failure, or host not found (different behaviour with different host and port names)

  • Verified the host and port from the working internal configuration

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Assistance Requested:

Kindly help me with the following points:

1. Network / Access Validation:

   • Confirm if the OData service endpoint is accessible externally (from my workstation or integration environment).

   • Verify if any network/firewall restrictions are preventing external HTTP(S) access to the given host/port.

2. Authentication Configuration:

   • Clarify which authentication mechanisms are supported for external OData access (Basic Auth, OAuth, or any other).Guiden enabling both types of authentication so that I can test successfully through Postman.

3. Connection Parameters:

   • Confirm the correct base URL, port, and path that should be used for external API consumption.

   • Any additional security or SSL configurations required (e.g., certificates or trusted CA setup).

4. Troubleshooting Guidance:

   • If possible, provide logs or trace locations (e.g., /IWFND/ERROR_LOG, /IWBEP/ERROR_LOG, or ST22 dumps) to check for incoming request failures.

   • Confirm if external access to OData requires SAP Gateway or reverse proxy configuration.

Goal:

To enable successful connection and data retrieval from the activated SAP OData service via Postman, and later integrate the same endpoint in my external application connector.

Thanks!