Unable to test/run Azure Function form the portal

Question

Getting this warning message when I am trying to test/run a function through the Azure portal.

Running your function in portal requires the app to explicitly accept requests from https://portal.azure.com. This is known as cross-origin resource sharing (CORS).

I've previously been able to test/run functions from the portal without any issues. Other users with the same permissions do not seem to have the same issue. I've tried with different browsers and computers and still getting the same issue.

Has anyone encountered this before and know how to fix the issue?

Answer 1

@Henry Lam Thanks for reaching out.

The issue should be observed for the same function app across to all users and not to specific user that login to azure portal.

The warning message you are seeing indicates that the cross-origin resource sharing (CORS) policy for your Azure Function app needs to be updated to explicitly allow requests from https://portal.azure.com.

Once you have updated the CORS policy, you should be able to test/run your function from the Azure portal without seeing the warning message.

1. Open the Azure portal and navigate to your Function app.
2. Under the "API" section, click on "CORS".
3. In the "Allowed Origins" section, add https://portal.azure.com to the list of allowed origins.

Click "Save" to save your changes.

If you continue to experience issues, you may need to clear your browser cache or try using a different browser to see if that resolves the issue.

Feel free to get back to me if you need any assistance.

Please "Accept Answer" if the answer is helpful so that it can help others in the community.

Answer 2

None of the answers work. I have both https://portal.azure.com and https://ms.portal.azure.com in CORS and still getting the same error.

Answer 3

Hello @Henry Lam

"To prevent malicious code execution on the client, modern browsers block requests from web applications to resources running in a separate domain. Cross-origin resource sharing (CORS) lets an Access-Control-Allow-Origin header declare which origins are allowed to call endpoints on your function app."

Refer - https://learn.microsoft.com/en-us/azure/azure-functions/functions-how-to-use-azure-function-app-settings#cors

https://learn.microsoft.com/en-us/azure/azure-functions/functions-how-to-use-azure-function-app-settings?tabs=portal#portal-3

Answer in MSDN

https://social.msdn.microsoft.com/Forums/en-US/ffb2067e-0846-450b-8665-0cd6199aad75/sudden-cors-client-error?forum=AzureFunctions#ffb2067e-0846-450b-8665-0cd6199aad75