Hospital Pre-authorization - Natural birth

I sent an email for a hospital Pre-authorization on the 2nd of September 2023. I'm due to deliver on the 4th of October 2023, however the baby might come early. I'll have Natural birth. Today 12 September 2023, I received an email telling me that, my request has been declined, for what. The procedure is covered by medical plan, so I don't understand why they'll decline.