400 Bad HTTP Request

[Ch_97]

Hello, SAP Community!

We’re encountering an HTTP 400 Bad Request error when attempting to send data to an external server via API from our SAP S/4HANA system. I’d like to share details about the issue and gather insights on possible solutions.

Issue Details:

1. Setup: SAP S/4HANA system using API for data transfer to an external server.

2. Error: HTTP 400 Bad Request received in the SAP system when trying to send the data.

3. SMICM Logs: The SMICM logs reveal the following error message:

   ERROR => HttpParseResponseHeader: illegal status code: 610; status reason: Undefined

4. Context: This error seems to point to an issue in parsing the response header. The status code 610 is unexpected, and "Undefined" status suggests there’s an invalid response format coming from the server.

Troubleshooting Steps Taken So Far:

1. Checked API Payload and Headers: Verified the JSON structure and ensured that the Content-Type is set to application/json.
2. Validated API Endpoint: Confirmed that the API endpoint URL and authentication parameters are accurate.
3. Network Check: Verified network connectivity between SAP S/4HANA and the external server, confirming no firewall or connectivity blocks.
4. icm/HTTP/max_request_size_KB parameter is currently set to its default value of 102400. We changed the parameter value dynamically in RZ11 to the maximum value, but the 400 Bad Request error persists

Questions for the Community:

1. Header Parsing Issue: Has anyone else encountered the “illegal status code: 610” error in SMICM logs? If so, what was the root cause, and how did you resolve it?
2. Additional Logging: Are there specific SAP transaction codes or logs where we could capture more detailed information about the HTTP request and response?
3. SMICM Configurations: Could this issue be related to specific SMICM settings, or might there be configuration parameters to adjust to handle unexpected status codes?

Any advice or shared experiences would be greatly appreciated! If you've dealt with similar HTTP response parsing issues in SAP S/4HANA, especially around undefined status codes, your insights could be immensely helpful in resolving this challenge.

Thank you in advance!

Thanks & Regards,
Hemachandiran R
SAP Basis Administrator

[Sandra_Rossi]

Standard HTTP status codes are between 100 and 599. https://en.wikipedia.org/wiki/List_of_HTTP_status_codes. I'm surprised that a non-standard code is rejected by the kernel. Use SICF menu > client > recorder to get the exact request and response. After that, you may also contact the SAP Support (I didn't find an SAP note about this message, but maybe https://me.sap.com/notes/2620715/E can give clues about the problem). NB: with the help of a developer, I would create my own web service on the same server, which returns 610, to test whether the kernel accepts a non-standard HTTP status code, that will prove that the problem is not directly due to 610.

[Isaías]

You could also verify why the external system returns a non-standard HTTP code... which would be wrong...