@Chandra It looks like the image you attached did not make it but I think I understand your issue. You are using the category parameter with the news search endpoint i.e the endpoint is https://api.cognitive.microsoft.com/bing/v7.0/news/search
Please try the same with just the news endpoint https://api.cognitive.microsoft.com/bing/v7.0/news
This is documented in the endpoints section and the news API reference.
Entertainment:
Politics:
Also, your endpoint seems to refer to cognitive services resource of bing, this is now migrated to bing and any new resource that is created uses https://api.bing.microsoft.com after Oct 30 2020.