Issue with CoAP POST – "No matching proxy rule" on custom server using nRF9151 (Lesson 5, Exercise 1)

RE: Issue with CoAP POST – "No matching proxy rule" on custom server using nRF9151 (Lesson 5, Exercise 1)

Achim Kraus — Mon, 28 Jul 2025 05:12:20 GMT

You're welcome.

RE: Issue with CoAP POST – "No matching proxy rule" on custom server using nRF9151 (Lesson 5, Exercise 1)

Priyesh Shahi — Mon, 28 Jul 2025 04:47:40 GMT

Thank you for the clarification regarding the 0x80 (4.00 Bad Request) response and the proxy behavior of the CoAP server.

I've resolved the issue with the help of our developer team. It turns out the server was expecting the hostname to be explicitly included in the CoAP request payload, which we had initially missed. Once we added that, the server started processing the requests correctly.

Appreciate your insights—it helped us narrow down the problem.

RE: Issue with CoAP POST – "No matching proxy rule" on custom server using nRF9151 (Lesson 5, Exercise 1)

Achim Kraus — Sun, 27 Jul 2025 09:26:57 GMT

I guess, you better ask that the developers of that server.

A response code uses 0bccc.ddddd (first 3 bits response class, last 5 bits details)

So a 0x80 is 4.00 => BAD REQUEST

If other servers are processing that request, then the request itself may not be the cause.

Why your own server doesn't want to process it, is something only you or the developers will be able to know.

[quote userid="129185" url="~/f/nordic-q-a/123273/issue-with-coap-post-no-matching-proxy-rule-on-custom-server-using-nrf9151-lesson-5-exercise-1"] "No matching proxy rule" [/quote]

That may be a hint, that your coap-server acts mainly as proxy and has no "matching rule" for your request.

RE: Issue with CoAP POST – "No matching proxy rule" on custom server using nRF9151 (Lesson 5, Exercise 1)

Priyesh Shahi — Sat, 26 Jul 2025 07:44:58 GMT