I Can´t connect my iphone 6 plus whith my Plantronics BachBeat fit.

Howdy mromina.cordero,

I understand that you're not able to get your headphones to connect to your new iPhone 6 plus, despite having them connected to your iPhone 5s. In such a situation, it may actually be the fact that the headphones are still paired with your iPhone 5s which is preventing you from pairing them with the new iPhone. The steps outlined below detail this and additional troubleshooting steps that can help get your devices paired and working.

1. Make sure that your Bluetooth accessory and iOS device are close to each other.
2. Make sure that your Bluetooth accessory is on and fully charged or connected to power. If it uses batteries, test them to see if they need to be replaced.
3. Restart your Bluetooth accessory.
4. Make sure that you have the latest version of iOS on your iPhone, iPad, or iPod touch.
5. On your iOS device, go to Settings > Bluetooth and make sure that Bluetooth is on. If you can’t turn Bluetooth on or you see a spinning gear, restart your iPhone, iPad, or iPod touch.
6. Unpair the Bluetooth accessory, put the accessory back in discovery mode, then pair and connect itagain.

Get help connecting a Bluetooth accessory with your iPhone, iPad, or iPod touch
https://support.apple.com/en-us/HT201205

Additional information can be found in the linked article, as well.

Regards!