Having troubles with the sync? Here are some reasons things can go wrong and how to fix it:
1. You're not in the same Wifi
The initial sync requires you to be on the same Wifi. Once that is done your sync happens via an end2end encrypted web connection. For now, make sure you're connected to the same network, or connect your computer to your phone's tethering connection.
2. Your Wifi network blocks the connection
Some routers have a firewall that block the (WebRTC) connection used for the initial sync between your computer and the phone. Try changing your network, or use your phone's tethering, which has shown to be very reliable.
3. You're trying to re-sync with a previously connected phone to another device.
In our 1.0 version we have not implemented the ability to unpair your device and re-pair it with another one. If you want to switch out a computer or a phone it is important that you first delete your app completely, and remove the list of paired devices manually in the extension settings (Go to settings ▸ Sync ▸ Remove). If you still run into problems contact our support team.
4. Some other app is blocking the WebRTC connection.
Do you have any extension running that could do that? One user reported having this extension installed: https://addons.mozilla.org/en-US/firefox/addon/happy-bonobo-disable-webrtc/