Hello @Philip Bae , Thanks for using Microsoft Q&A Platform.
Generally, as per the error message "Resource not found" with code 404 indicates that the requested resource is not available. This error can occur due to various reasons, such as incorrect/expired subscription key, or invalid URL.
To troubleshoot this issue, please ensure that you have entered the correct URL and subscription key. You can also try regenerating either one of the subscription keys in the Azure portal to see if it resolves the issue.
Also please note the following information, this may also impact in your situation:
Bing Search APIs will transition from Azure Cognitive Services to Azure Marketplace on 31 October 2023. The existing instances of the following Bing Search APIs under Azure Cognitive Services will no longer be supported after 31 October 2023. You can continue to create new instances of Bing Search APIs under the Azure Marketplace. https://azure.microsoft.com/en-ca/updates/bing-search-apis-will-transition-from-azure-cognitive-services-to-azure-marketplace-on-31-october-2023/
I hope this helps.
Regards,
Vasavi