Azure Logic App not find an Azure Function

Question

Azure Logic App not find an Azure Function

Bernard Brown 100

Hi,

I'm trying to use a Logic App to run an Azure Function with an HTTP Trigger. I've tried using a Function and an HTTP Action. Using either one fails and gives me a 404 not found. Oddly enough, using Postman, I can successfully run the function with it's URL.

Can someone help me with this? LA_HTTP_Error

LA_HTTP_Error

Postman_success

Jerald Felix 9,835 Reputation points

2025-11-16T16:55:38.43+00:00
Hello Bernard Brown,

The 404 Not Found error when calling an Azure Function HTTP trigger from Logic Apps (both Function and HTTP actions) but succeeding in Postman is a classic integration issue, typically caused by authentication mismatches (Function key required), networking restrictions, or endpoint resolution—Logic Apps uses managed identity by default, while Postman likely includes the function key. Here's how to fix it:

Quick Diagnosis and Fixes

Check Authentication (Most Common):

Functions require the function key for AuthorizationLevel.Function (default). Postman works because you added it; Logic Apps doesn't.

Fix for Function Action: Portal > Logic App > Add action > Azure Functions > Select function > It prompts for "Function key"—copy from Function > Functions > Your function > Function keys > Default (function) key > Paste.

For HTTP Action: Method: POST/GET > URI: https://yourfunction.azurewebsites.net/api/yourfunction?code=YOUR_FUNCTION_KEY (append key to query string).

Test: Save flow > Run > Check run history inputs (should show key in URI/headers).

Verify Endpoint and Networking:

Function URL: Ensure URI matches exactly (e.g., /api/FunctionName not /FunctionName). Get from Function > Overview > Get function URL (includes code= key).

Access Restrictions: Function App > Networking > Access restrictions > If rules exist, add Logic App's outbound IP (Logic App > Properties > Outbound IP addresses) as Allow.

VNet/Private Endpoint: If Function in VNet, Logic App must be in same VNet or use Private Link (Integration > VNet).

Alternative HTTP Action Setup (Reliable):

Add "HTTP" action (not Function) >

Method: POST (or your method)

URI: https://yourfunction-app.azurewebsites.net/api/your-function-name

Headers: {"x-functions-key": "YOUR_DEFAULT_FUNCTION_KEY"} (use key header instead of query for security).

Body: Your payload (JSON/form).

Logic Apps Managed Identity: If Function set to AuthorizationLevel.Anonymous, skip key; else use above.

Troubleshooting:

Run History: Logic App > Runs > Failed run > Expand action > Inputs show URI/headers sent; Outputs show 404 response (no body usually).

Function Logs: Function App > Monitoring > App Insights > Logs > KQL: requests | where resultCode == 404—confirms calls arrive but fail auth.

Cross-Region: Ensure Logic App and Function in same region (e.g., East US); cross-region adds latency/404 if firewalls block.

Premium Connectors: If using Function connector (premium), ensure subscription active.

Use the HTTP action with function key header—resolves 90% of cases. Test with simple payload first. If persists, share URI format or logs for more.

Best Regards,

Jerald Felix
Bernard Brown 100 Reputation points

2025-11-16T21:23:54.7733333+00:00

OK. This is weird. I created a new Logic App to ensure I didn't do anything wrong in creating it. I tried both Function and HTTP actions. They are both working, but when they are run they still reports as failed runs.

Function never prompted me for the key. I selected the function and set the method and it worked. I checked the Logs in the function and I see that it's hitting both my HTTP start function and it's triggering the actual function that runs.

For HTTP, I copied the function's default URL, with the key, once again into URL and it worked. I removed the code and key and added them under Queries and that worked. As with Function, I can see in the function's logs that both functions were executed.

However, when I look at the Logic Apps Run History, I have nothing but failed jobs with 404s.
Praveen Kumar Gudipudi 1,495 Reputation points Microsoft External Staff Moderator

2025-11-17T09:43:33.51+00:00

Hello Bernard Brown,

could you please share me the RAW output of http action to proceed further on this issue?

Bernard Brown 100

Hi Praveen,

Here it is:

{
    "statusCode": 404,
    "headers": {
        "Date": "Mon, 17 Nov 2025 11:15:59 GMT",
        "Request-Context": "appId=cid-v1:ba63522f-6428-49fe-8e4c-db470f105490",
        "Content-Length": "0"
    }
}

Bernard Brown 100 Reputation points

2025-11-18T16:35:15.1566667+00:00

Praveen, the suggested changes worked. I'm now getting a successful run in the history.

Answer accepted by question author

0 additional answers

Your answer

Bernard Brown 100 Reputation points

2025-11-16T21:23:54.7733333+00:00

OK. This is weird. I created a new Logic App to ensure I didn't do anything wrong in creating it. I tried both Function and HTTP actions. They are both working, but when they are run they still reports as failed runs.

Function never prompted me for the key. I selected the function and set the method and it worked. I checked the Logs in the function and I see that it's hitting both my HTTP start function and it's triggering the actual function that runs.

For HTTP, I copied the function's default URL, with the key, once again into URL and it worked. I removed the code and key and added them under Queries and that worked. As with Function, I can see in the function's logs that both functions were executed.

However, when I look at the Logic Apps Run History, I have nothing but failed jobs with 404s.
Praveen Kumar Gudipudi 1,495 Reputation points Microsoft External Staff Moderator

2025-11-17T09:43:33.51+00:00

Hello Bernard Brown,

could you please share me the RAW output of http action to proceed further on this issue?
Bernard Brown 100 Reputation points

2025-11-17T11:28:04.8733333+00:00

Hi Praveen,

Here it is:

{ "statusCode": 404, "headers": { "Date": "Mon, 17 Nov 2025 11:15:59 GMT", "Request-Context": "appId=cid-v1:ba63522f-6428-49fe-8e4c-db470f105490", "Content-Length": "0" } }
Bernard Brown 100 Reputation points

2025-11-18T16:35:15.1566667+00:00

Praveen, the suggested changes worked. I'm now getting a successful run in the history.

Answer 1

Praveen Kumar Gudipudi 1,495 Microsoft External Staff Moderator

Hello Bernard Brown,

Please try below suggested steps:

Turn OFF “Asynchronous Pattern” in Logic Apps.
Implement retry policy. Please check above suggested steps and let me know with an update.

Please accept as answer and do a Thumbs-up to upvote this response if you are satisfied with the community help. Your upvote will be beneficial for the community users facing similar issues.

User's image

Praveen Kumar Gudipudi 1,495 Reputation points Microsoft External Staff Moderator

2025-11-20T10:52:12.08+00:00

Hello Bernard Brown,

Just checking in to see if the below suggestion helped. If this answers your query, do click Accept Answer and Yes for was this answer helpful. And, if you have any further query do let us know.

As your feedback is valuable and can assist others in the community facing similar issues.

Share via

Azure Logic App not find an Azure Function

Quick Diagnosis and Fixes

0 additional answers

Your answer