404 Not Found page appearing on first position

Hi,

I am a medical biller and trying to find correct department of insurance on Bing but unfortunately Bing is suggesting me a website with 404 (screenshot attached). I tried to fix it by updating edge to latest version but the error is still appearing. Can you help me to fix this issue?

Here is the link: https://www.rcmguide.com/bcbs-prefix-list/