I am creating a new app and getting this error, "The app name you entered is already being used", even though I searched on App Store and no such app exists, moreover I have trademark rights for this name. Can someone please help me in this regard?
Maybe check and see if you have already registered the name you're trying to use with your personal account. If so, you'll need to contact Apple Developer Programs for help moving it over to your developer account.
You can contact Apple Developer Programs support using the options displayed on this page ~ https://developer.apple.com/contact/topic/select