How to connect a Droplet hosting a site to an app hosting an API

I have a DO app with a react application. This application connects to my DO Droplet to retrieve some search results.

When I attempt to connect from my development environment the Droplet, it returns data and the locally deployed react app displays the data.

However, when I deploy the react app onto the Droplet I receive the error: Unhandled Rejection (TypeError): Not allowed to request resource

This originates in the applications request to the API hosted on the droplet. I have attempted both the public IP for the droplet as well as the private IP. The same issue occurrs once the application is deployed on the DO app.

What areas can I look at where there might be an issue?

const fetchReferences = async () => {

fetch(‘http://xxx.xxx.xxx.xxx:8080/search/’, {. //this is the line that errors. method: ‘POST’, body: JSON.stringify({ url: searchState.searchCriteria