I think we need more info here. I'm guessing this is a locally hosted site? How are you exposing it to the web? DDNS? Reverse proxy? Honestly it's hard to diagnose without knowing your IP, which you definitely shouldn't give us.
Edit: you can check your site here, maybe they'll give you details on why it was blacklisted: https://transparencyreport.google.com/safe-browsing/search