Electron App (React) POST net::ERR_FILE_NOT_FOUND

I've run into an issue where when I run electron-package on my app and run the built app, when I try to access a route besides the default route I get a net::ERR_FILE_NOT_FOUND. I have a login page and when I try clicking log in I get: POST file:///logIn net::ERR_FILE_NOT_FOUND

this is my electron.js

const electron = require('electron');
const { app, BrowserWindow } = electron;
const path = require('path');
const isDev = require('electron-is-dev');
const url = require('url');

let mainWindow = null;
const createWindow = () => {
    mainWindow = new BrowserWindow({
        width: 1024, height: 1024,
        autoHideMenuBar: true,
        useContentSize: true,
        resizable: true,
        webPreferences: {
            nodeIntegration: true,
            devTools: true
        }

    })


    mainWindow.loadURL(`file://${__dirname}/../build/index.html#/`);

    mainWindow.on('closed', () => mainWindow = null)

    mainWindow.webContents.openDevTools();


}

app.on('ready', createWindow)

app.on('window-all-closed', () => {
    if (process.platform !== 'darwin') { app.quit() }
})

app.on('activate', () => {
    if (mainWindow === null) { createWindow() }
})

package.json

"main": "public/electron.js",
  "homepage": "./",
  "name": "security-tool",
  "version": "0.1.0",
  "private": true,
  "build": {
    "appId": "",
    "extends": null,
    "files": [
      "node_modules/**/*",
      "package.json",
      "electron.js",
      "build/**/*"
    ],
    "directories": {
      "buildResources": "assets"
    }
  },

and just index.js

ReactDOM.render(
  <CookiesProvider>
    <HashRouter>
      <Switch>
        <Route path="/home" component={Home} />
        <Route path="/projects" component={Projects} />
        <Route path="/settings" component={Settings} />
        <Route path="/form" component={Form} />
        <Route exact path="/" component={Login} />
      </Switch>
    </HashRouter>,
  </CookiesProvider>,
  document.getElementById('root')
);

can't show the entire login component but this is the part which has history.push

logIn = async() => {
  let results = await logInEndpoint(this.state.Username, this.state.Password);
      if(results.result === "Success!") {
        const { cookies } = this.props;
 
        cookies.set('userID', results.data[0].USER_ID, { path: '/', maxAge: 3600 });

        this.props.history.push('/home');
      }
      else{
        this.invalidCreds(results.result);
      }
  }