How To Fix GEF_CORE_MSG049 - Callback is not supported. For cross site requests, CORS is recommended.

SAP Error Message - Details

• Message type: E = Error

• Message class: GEF_CORE_MSG - Message class for GEF core

• Message number: 049

• Message text: Callback is not supported. For cross site requests, CORS is recommended.

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message GEF_CORE_MSG049 - Callback is not supported. For cross site requests, CORS is recommended. ?

  The SAP error message GEF_CORE_MSG049 indicates that a callback is not supported for cross-site requests, and it suggests using CORS (Cross-Origin Resource Sharing) as a solution. This error typically arises in scenarios where a web application is trying to make requests to a different domain, protocol, or port than the one from which it was served.
  Cause:
  
  Cross-Origin Requests: The error occurs when a web application attempts to make a request to a different origin (domain, protocol, or port) without the proper CORS configuration.
  Callback Mechanism: The application may be trying to use a callback function that is not supported in the context of cross-origin requests.
  Security Restrictions: Browsers enforce the Same-Origin Policy for security reasons, which restricts how a document or script loaded from one origin can interact with resources from another origin.
  
  Solution:
  To resolve this error, you can implement CORS in your SAP application. Here are the steps to do so:
  
  
  Enable CORS on the Server:
  
  Configure the server to include the appropriate CORS headers in the response. This typically involves adding the Access-Control-Allow-Origin header to allow requests from specific origins or all origins (*).
  Example headers to include:
  Access-Control-Allow-Origin: https://your-allowed-origin.com
  Access-Control-Allow-Methods: GET, POST, OPTIONS
  Access-Control-Allow-Headers: Content-Type, Authorization
  
  
  
  
  Modify the SAP Gateway Configuration:
  
  If you are using SAP Gateway, you may need to adjust the settings in the SAP Gateway to allow CORS. This can often be done through transaction codes like /IWFND/MAINT_SERVICE or /IWFND/GW_CLIENT.
  
  
  
  Check for Preflight Requests:
  
  For certain types of requests (like those using methods other than GET or POST, or with custom headers), the browser will send a preflight OPTIONS request. Ensure that your server is configured to handle these OPTIONS requests correctly.
  
  
  
  Testing:
  
  After making the necessary changes, test the application to ensure that the error is resolved and that cross-origin requests are functioning as expected.
  
  
  
  Related Information:
  
  CORS Documentation: Familiarize yourself with the CORS specification and how it works. The Mozilla Developer Network (MDN) has a comprehensive guide on CORS.
  Browser Developer Tools: Use the developer tools in your browser (usually accessible via F12) to inspect network requests and responses. This can help you identify if the CORS headers are being sent correctly.
  SAP Notes: Check SAP Notes and documentation for any specific configurations or updates related to CORS and the error message you are encountering.
  
  By following these steps, you should be able to resolve the GEF_CORE_MSG049 error and successfully implement cross-origin requests in your SAP application.