I followed the steps as mentioned in this page. Even though I created the API Management instance, on clicking the Test option in the Portal, it did not auto-populate Ocp-Apim-Subscription-Key. On clicking Send, I got the below error
{
"statusCode": 401,
"message": "Access denied due to missing subscription key. Make sure to include subscription key when making requests to an API."
}
I tried the Developer Portal option but got the same result. Please let me know if any other details are needed for reproducing/replicating the issue.
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@sudeep-sol Can you make sure you assigned a "Product" to your API? If not, please see if it works once you do.

Excellent!!! The response was quick and it fixed the issue. Can this be documented in the same page?
Yes, we missed it, I will add it to the doc. Glad it worked and thanks for catching it.
Closing the issue as the solution provided in the screenshot worked fine
Most helpful comment
Yes, we missed it, I will add it to the doc. Glad it worked and thanks for catching it.