Cross-Origin Request Blocked

I just deployed my project to Netlify:
I can make api calls on my local server with no issues. When I try to send a request through the hosted site I get this error:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:3000/?q=t.json. (Reason: CORS request did not succeed).

I’ve allowed all origins to make requests to my api but Netlify still triggers a CORS error. I’m not too sure where to go from here.

Why are you trying to connect to localhost from your website?