Troubleshooting "Unauthorized" errors when calling Azure API Management with B2C

hampton123 1,160

Currently I've been following this tutorial to integrate Azure API Management with B2C: https://learn.microsoft.com/en-us/azure/api-management/howto-protect-backend-frontend-azure-ad-b2c.

I have the system for B2C working, however when I call the API through pressing the "Call API" button after logging in, I receive an error "GET {API link}" 404 (Not Found)". When I load the API link in the next tab, it states a 401 unauthorized status code. I'm not sure how to address this issue.

Please let me know if I need to provide any additional context.

EDIT: I neglected to mention that the HTML itself states "SyntaxError: Unexpected end of JSON input" as the error. The 404 GET error is from inspecting the page and looking into the error.

MuthuKumaranMurugaachari-MSFT 22,276 Reputation points

2023-07-20T13:52:59.24+00:00

Hunter B Thanks for posting your question in Microsoft Q&A. If you can share the full error message including request ID or correlation id, timestamp etc. that would be helpful.
hampton123 1,160 Reputation points

2023-07-20T14:08:20.22+00:00
Hello @MuthuKumaranMurugaachari-MSFT

"Error: SyntaxError: Unexpected end of JSON input" is on the HTML page when the "Call API" button is used --> This is the main issue I am trying to fix.

"Failed to load resource: the server responded with a status of 404 (Not Found)" is the message displayed when the browser is inspected

"{ "statusCode": 401, "message": "Unauthorized. Access token is missing or invalid." }" is what is displayed on the link associated with the failed GET request, this is the link to the API.

Please let me know if I can provide more information.
MuthuKumaranMurugaachari-MSFT 22,276 Reputation points

2023-07-20T14:37:06.91+00:00

Hunter B thanks for sharing it. These messages appear generic, and I am looking for request ID/correlation ID, timestamp to investigate the backend logs. If you couldn't find it, it would be better to open a ticket with azure support team to assist you further.
hampton123 1,160 Reputation points

2023-07-24T16:33:45.87+00:00

Sorry about that MuthuKumaranMurugaachari-MSFT, my correlation ID with this issue is 8fd4432a-9ad4-4add-b857-34c0afdf9b9a.

The specific error now says "Error Signing in:ServerError: invalid_grant: undefined - [undefined]: AADB2C90205: This application does not have sufficient permissions against this web resource to perform the operation."
hampton123 1,160 Reputation points

2023-07-31T15:30:18.8066667+00:00
Hi MuthuKumaranMurugaachari-MSFT would the issue be with the Azure Function that is associated with the API? Currently my Azure Function's programming language does not match the tutorial's Azure Function's programming language; I'm using NodeJS while the tutorial uses C#.

Also if it helps, my code is crashing at the below section of the HTML - it's located in the script section of the HTML so it is Javascript:

const headers = new Headers()
MuthuKumaranMurugaachari-MSFT 22,276 Reputation points

2023-07-31T15:38:23.3766667+00:00

Hunter B I think we would need little more details about the issue/exception. Please send an email to azcommunity@microsoft.com referencing this thread with your subscription ID, details and subject as "Attn: Muthu". I will connect with you offline and assist you further.

Accepted answer

MuthuKumaranMurugaachari-MSFT 22,276 Reputation points

2023-08-09T15:35:47.98+00:00

Hunter B Thanks for your patience and sharing it with us.

Update for the community:

Initially when following the tutorial, App registrations were not created under Azure AD B2C. Then after assigning necessary permissions and troubleshooting, Hunter B figured out that Azure Function name was created incorrectly i.e., HttpTrigger1 vs hello in the tutorial. Hence, the API call was made incorrectly and returned the above error.

He corrected the function name and it worked successfully.
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1 person found this answer helpful.
hampton123 1,160 Reputation points

2023-08-09T16:08:38.7666667+00:00

Thank you for your assistance again MuthuKumaranMurugaachari-MSFT, you were a great help!
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Troubleshooting "Unauthorized" errors when calling Azure API Management with B2C

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