# Troubleshooting

## I followed the installation and usage instructions but still experience CORS issues on device

Sometimes `cordova-plugin-advanced-http` displays as installed but in fact it's not which forces the lib to fall back to XMLHttpRequest usage.

To make sure `cordova-plugin-advanced-http` is installed correctly and works properly change any project's page class to correspond the code below. The example below is for `HomePage`.

```typescript
import { Platform } from 'ionic-angular';
import { HTTP } from '@ionic-native/http';

export class HomePage {
    constructor(
        private platform: Platform,
        private nativeHttp: HTTP,
    ) {
        this.platform.ready().then(() => {
            this.nativeHttp.post('https://httpbin.org/post', {a: 'b'}, {})
                .then(() => {
                    console.log('cordova-plugin-advanced-http is installed properly');
                });
        });
    }
}
```

Run the app on device and watch console output. Absence of the message `cordova-plugin-advanced-http is installed properly` in console output says `cordova-plugin-advanced-http` has not been installed or recognized. Try to reinstall it and give it another chance.