Docker React-.NET 6 Web API Connection Problem - reactjs

Question

I have a React and .NET 6 project, each in separate containers and brought up together on the same Docker Virtual Network via Docker Compose. Both start and run fine but the React frontend is unable to communicate to the backend.
For whatever reason, I can access the weather api on my backend using my browser (doesn't work on the frontend) but not any other endpoint. https://localhost:5001/api/weatherforecast returns the generated weather data (default tutorial weather api).
But when I go to other endpoints like https://localhost:5001/api/user?userId=1, I get the following: Error: The SSL connection could not be established, see inner exception.
I'm not sure if it is an issue with the setupProxy.js or something wrong with the self-signed cert on the .NET backend.
docker-compose.yml
version: "3.8"
networks:
api-network:
services:
server:
build:
context: ./server-testing/server
args:
PROXY: ${PROXY}
container_name: 'server'
ports:
- '5000:5000'
- '5001:5001'
networks:
- api-network
environment:
- ASPNETCORE_ENVIRONMENT=Development
- ASPNETCORE_Kestrel__Certificates__Default__Password=${PW}
- ASPNETCORE_Kestrel__Certificates__Default__Path=/https/aspnetapp.pfx
volumes:
- ~/.aspnet/https:/https:ro
client:
build:
context: ./client
args:
PROXY: ${PROXY}
container_name: 'client'
depends_on:
- server
ports:
- '3000:3000'
networks:
- api-network
stdin_open: true # Keep STDIN open even if not attached
tty: true # Allocate a pseudo-TTY
Frontend Setup
The build is served by an nginx layer to serve a production React build.
In my package.json, I have "start": "set HTTPS=true&&react-scripts start" instead of "start": "react-scripts start".
// setupProxy.js
const { createProxyMiddleware } = require('http-proxy-middleware');
const context = [
"/api"
];
module.exports = function (app) {
const appProxy = createProxyMiddleware(context, {
target: 'https://server:5001/',
secure: false,
changeOrigin: true
});
app.use(appProxy);
};
Backend Setup
Self-signed certs generated with dotnet dev-certs https -ep %USERPROFILE%\.aspnet\https\aspnetapp.pfx -p { password here }
Three endpoints:
/weatherforecast
/user/
/cart/
Endpoints are accessed as https://localhost:5001/api/endpoint?params
If you need any more information, please let me know. Thanks!