Hi @tooltester
Thank you for using the Microsoft Q&A forum.
If you are receiving the error message "Unable to execute your query. Ensure that a valid subscription key has been set up for your instance", while using Bing Custom Search, it means there is an issue with your subscription key. Even if you believe your subscription key is valid, there could be other reasons why it is not working. To troubleshoot the issue, you can double-check your subscription key, ensure you are using the correct endpoint, verify your resource permissions, and check your API quota.
To troubleshoot the issue further, please try with simple CURL command with the endpoint and same subscription key in CMD prompt, to find out exactly what could be the issue.
See example below. This is just for troubleshooting purposes.
curl -H "Ocp-Apim-Subscription-Key: YOUR_KEY" "https://api.bing.microsoft.com/v7.0/search?q=google&textFormat=HTML&count=10"
If you have tried all of these steps and are still experiencing issues, I request you to raise a support case through Azure portal.
Thank you.