Troubleshoot API(s) imported via self-hosted gateway

Question

Troubleshoot API(s) imported via self-hosted gateway

Deepakraj P 0

If I expose an API which is running in a VM in a specific port to internet, and import it to Azure APIM via managed gateway, it is working fine. API is accessible with get operation and URL scheme set to https though the API is http only. But the same API when imported via self-hosted gateway which is running in AKS cluster, the error states below error in logs.
lastError: {"source":"configuration","reason":"OperationNotFound","message":"Unable to match incoming request to an operation.","section":"backend"}

AKS has access to specific port on the VM where API is running. What could be the issue, how to troubleshoot and resolve it?

Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-02T10:54:52.5433333+00:00

@Deepakraj P ,

Can you confirm the network connectivity, API import status, and request routing behavior between the self-hosted gateway and the backend API, including protocol handling and any applied policies?
Deepakraj P 0 Reputation points

2025-04-02T12:31:01.0933333+00:00

There are no policies as of now. Published the API with subscription key. API import is correct (as it is manual add), added operations. Connectivity is correct from AKS to the VM (on specific port where API is running, as instructed), from AKS (self-hosted gateway pod) able to get response for the API with http://<Public-IP>:<Port>/test (test is the relative path for this test API).

My biggest concern is the same API if API is exposed to internet, and imported via Managed gateway it is working fine. the same if replicated and imported via self-hosted gateway getting 404. Now lately, started to get 500 as well. In the early error logs used to get Unable to match incoming request to an operation.
Loknathsatyasaivarma Mahali 1,375 Reputation points Microsoft External Staff

2025-04-03T17:39:56.52+00:00

Hello @Deepakraj P,

I have sent you a private message. Could you kindly check and respond at your earliest convenience so that we can proceed with troubleshooting the issue?
Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-04T14:00:35.73+00:00
@Deepakraj P ,
Basically we get 404 error in APIM because of the following reasons:

HTTP Method Mismatch: The incoming request must match both the path and the HTTP method (GET, POST, etc.) as defined in the APIM operation. A mismatch (e.g., sending a GET request to a POST operation) will result in a 404 with OperationNotFound.

Incorrect URL Path or Base Path:

The requested URL might include an incorrect path, trailing slash, or casing (e.g., /test/ vs /test).

Ensure the request follows the exact API base path + operation path as defined in APIM.

Protocol Mismatch:

While APIM may expose the API via HTTPS, the actual backend might only support HTTP.

Ensure that the protocol is correctly handled either via policies or backend configuration.

Self-Hosted Gateway Configuration Not Synced:

If using a self-hosted gateway (e.g., in AKS), it’s important to ensure the configuration has been fully synced with the latest version from Azure.

You can trigger a manual config refresh or check logs to confirm successful synchronization. Please check and let us know if you could able to resolve the issue.
Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-07T12:05:59.2366667+00:00

@Deepakraj P ,

Just following up again to see if you were able to resolve the issue or if there's anything else I can assist you with.
Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-08T15:06:01.59+00:00

@Deepakraj P ,

Could you please let us know if you are still facing the issue?
Deepakraj P 0 Reputation points

2025-04-22T13:23:16.78+00:00

Still the issue is there Khadeer. Couldn't figure out where the issue is arising. If I can get anywhere from application insights or log analytics workspace logs of what is the cause instead of plain text saying "Configuration error", "Unable to match incoming request", "Operation not found" or "Resource not found", we can debug easily.
Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-22T15:06:07.1666667+00:00

@Deepakraj P ,

Could you please share the details I requested in the private message?

1 answer

Your answer

Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-02T10:54:52.5433333+00:00

@Deepakraj P ,

Can you confirm the network connectivity, API import status, and request routing behavior between the self-hosted gateway and the backend API, including protocol handling and any applied policies?
Deepakraj P 0 Reputation points

2025-04-02T12:31:01.0933333+00:00

There are no policies as of now. Published the API with subscription key. API import is correct (as it is manual add), added operations. Connectivity is correct from AKS to the VM (on specific port where API is running, as instructed), from AKS (self-hosted gateway pod) able to get response for the API with http://<Public-IP>:<Port>/test (test is the relative path for this test API).

My biggest concern is the same API if API is exposed to internet, and imported via Managed gateway it is working fine. the same if replicated and imported via self-hosted gateway getting 404. Now lately, started to get 500 as well. In the early error logs used to get Unable to match incoming request to an operation.
Loknathsatyasaivarma Mahali 1,375 Reputation points Microsoft External Staff

2025-04-03T17:39:56.52+00:00

Hello @Deepakraj P,

I have sent you a private message. Could you kindly check and respond at your earliest convenience so that we can proceed with troubleshooting the issue?
Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-04T14:00:35.73+00:00

@Deepakraj P ,
Basically we get 404 error in APIM because of the following reasons:

HTTP Method Mismatch: The incoming request must match both the path and the HTTP method (GET, POST, etc.) as defined in the APIM operation. A mismatch (e.g., sending a GET request to a POST operation) will result in a 404 with OperationNotFound.

Incorrect URL Path or Base Path:

The requested URL might include an incorrect path, trailing slash, or casing (e.g., /test/ vs /test).

Ensure the request follows the exact API base path + operation path as defined in APIM.

Protocol Mismatch:

While APIM may expose the API via HTTPS, the actual backend might only support HTTP.

Ensure that the protocol is correctly handled either via policies or backend configuration.

Self-Hosted Gateway Configuration Not Synced:

If using a self-hosted gateway (e.g., in AKS), it’s important to ensure the configuration has been fully synced with the latest version from Azure.

You can trigger a manual config refresh or check logs to confirm successful synchronization. Please check and let us know if you could able to resolve the issue.
Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-07T12:05:59.2366667+00:00

@Deepakraj P ,

Just following up again to see if you were able to resolve the issue or if there's anything else I can assist you with.
Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-08T15:06:01.59+00:00

@Deepakraj P ,

Could you please let us know if you are still facing the issue?
Deepakraj P 0 Reputation points

2025-04-22T13:23:16.78+00:00

Still the issue is there Khadeer. Couldn't figure out where the issue is arising. If I can get anywhere from application insights or log analytics workspace logs of what is the cause instead of plain text saying "Configuration error", "Unable to match incoming request", "Operation not found" or "Resource not found", we can debug easily.
Khadeer Ali 4,705 Reputation points Microsoft External Staff

2025-04-22T15:06:07.1666667+00:00

@Deepakraj P ,

Could you please share the details I requested in the private message?

Answer 1

Hi everyone who's looking for answer or following up on this question, I would like to let you know that the issue has been resolved. In fact, there is no issue at all. If I'm importing and managing API via self-hosted gateway I won't get response for APIM endpoint even in test tab. Don't understand why no one has mentioned about that so far. You will get the intended response if you just replace APIM endpoint with Loadbalancer IP of the service deployed as part of self-hosted gateway. Don't forget to use correct protocol, if not you'll get same 404 Operation Not Found error.

Hope it helps everyone. Happy exploring.

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Troubleshoot API(s) imported via self-hosted gateway

1 answer

Your answer