Understanding the Error [aadsts900561: the endpoint only accepts post, options requests. received a get request.]
Encountering an error like “[aadsts900561: the endpoint only accepts post, options requests. received a get request.]” can be confusing and frustrating, especially when dealing with authentication or API-related processes. This error is primarily associated with Microsoft’s Azure Active Directory (AAD) and arises due to incorrect handling of HTTP requests, particularly the GET and POST methods.
Let’s break down the error and look into its causes, how it manifests, and what steps you can take to resolve it.
What Is the Nature of This Error?
At its core, this error occurs when an endpoint that is designed to handle POST or OPTIONS requests receives a GET request instead. In the context of Azure Active Directory (AAD), this typically happens during an OAuth or OpenID Connect flow where the client makes an inappropriate request type.
In simpler terms, the aadsts900561 error is triggered when a resource is configured to accept specific request methods (POST or OPTIONS), but instead, a request is sent using the GET method. Since GET and POST requests are fundamentally different in how they handle data, this mismatch leads to the server rejecting the request, resulting in the error.
How the Error Manifests for Users
When users or developers encounter the [aadsts900561: the endpoint only accepts post, options requests. received a get request.] error, it usually manifests in authentication workflows. For example, during an OAuth flow when attempting to authenticate with Azure AD or when connecting applications to the Azure ecosystem. The user may experience authentication failures, redirection issues, or interruptions in accessing the required resources. In web applications, this often appears as an error message in the console or an error page, depending on how the application handles exceptions.
Common Causes of the Error
There are several reasons why this error might occur. Below are some common causes:
- Incorrect Configuration of OAuth/OIDC Flow: When setting up OAuth or OpenID Connect authentication, improper configuration of the endpoints can lead to mismatched request types.
- Misrouted HTTP Requests: If a client makes a GET request to an endpoint that expects a POST request (for example, when submitting form data), the server will reject the request.
- Cache Issues: Sometimes, cached GET requests can be inadvertently used in place of a POST request, triggering this error.
- Client-Side Coding Errors: In some cases, application code may incorrectly route requests, using the GET method when POST or OPTIONS is required.
Real-World Examples from User Feedback
In several online forums, such as Stack Overflow and GitHub, users have shared their experiences with the [aadsts900561: the endpoint only accepts post, options requests. received a get request.] error. One common scenario involves developers working with Single Sign-On (SSO) integrations, where this error appears after logging in or authenticating through Azure Active Directory. In these cases, the error often results from using the wrong request method during a token exchange process.
Another real-world example comes from developers configuring APIs on Microsoft’s Azure portal. During testing, they might accidentally trigger the GET request instead of POST, resulting in the error message. In such cases, the developers typically need to adjust the API configuration to match the expected request type.
Troubleshooting and Resolving the Error
Now that we understand the causes and nature of this error, let’s dive into how to resolve it. Here is a step-by-step guide to troubleshooting the [aadsts900561: the endpoint only accepts post, options requests. received a get request.] error:
Step 1: Check the Request Method
The first step in resolving this error is to check the request method being sent to the endpoint. If the request is a GET, you’ll need to modify it to either a POST or OPTIONS request as required by the endpoint.
- How to Check: Use your browser’s developer tools (usually available under the “Network” tab) to inspect the HTTP requests made by the client. Look for the method type (GET, POST, etc.) for the failed request.
- Solution: If the method is GET, modify the request to POST or OPTIONS depending on the server’s requirements.
Step 2: Adjust the API or Authentication Flow Configuration
If you are working with an OAuth or OpenID Connect authentication flow, make sure the flow is correctly configured.
- How to Adjust: In the application’s configuration settings, ensure that the appropriate request methods are being used for authentication requests. For instance, a token exchange or form submission should always use POST.
- Example: In your OAuth client setup, make sure the redirect URIs and token exchange endpoints are set to handle POST requests.
Step 3: Clear Browser or Client-Side Cache
Sometimes, the error can be triggered due to cached GET requests being reused.
- How to Clear Cache: Go to your browser settings and clear the cache and cookies. If you’re using a client application, verify that old requests aren’t being cached inadvertently.
- Result: Once the cache is cleared, the correct POST requests should be sent to the endpoint.
Step 4: Update or Fix Client-Side Code
If the error originates from incorrect client-side routing, you’ll need to update your code.
- Solution: Check your JavaScript or client-side code to ensure that the correct method (POST or OPTIONS) is being used when calling the endpoint.
- Tip: Make sure that any form submissions or API calls within your code are explicitly defined as POST or OPTIONS requests.
Step 5: Review and Test Endpoint Configuration
Finally, make sure that the server-side configuration matches the type of requests the client is sending.
- Check: Go to your Azure portal and review the endpoint configuration. Ensure that endpoints expecting POST requests are not inadvertently allowing or defaulting to GET requests.
- Test: After making changes, test the authentication or API call to ensure the error is resolved.
Preventing the Error in the Future
To prevent encountering the [aadsts900561: the endpoint only accepts post, options requests. received a get request.] error in the future, follow these best practices:
- Ensure Consistent Configuration: When setting up authentication flows or APIs, double-check that the correct request methods are used at every stage of the process.
- Clear Caches Regularly: Cached requests can often cause unexpected behavior. Make it a habit to clear caches in your development environment to avoid potential conflicts.
- Monitor Changes in Azure: Keep track of updates or changes in Azure Active Directory services that may impact your configuration. Always test changes in a development environment before pushing them to production.
- Use Proper Error Handling: Implement robust error handling in your code to capture and log issues like these, allowing you to troubleshoot more effectively in the future.
Conclusion
The error [aadsts900561: the endpoint only accepts post, options requests. received a get request.] can be frustrating, but with the right understanding and approach, it is easily resolvable. By ensuring that the correct HTTP request methods are used, adjusting configurations, and regularly clearing caches, you can avoid this issue and maintain a smooth authentication or API workflow. Implementing the troubleshooting steps outlined in this article will help you resolve the error quickly and prevent similar problems from occurring in the future.
