Garmin fenix 7x pro Bluetooth. After pairing the phone, the Bluetooth connection is lost. no data exchange

Hello Vova198106

I am sorry to hear you are having this issue. If this is still occurring, I would recommend trying the following initial troubleshooting steps: 

• Ensure the Connect Mobile app is on the latest version, as well as the phone's OS. 
• Powercycle the phone
• Complete a hard reset on the watch. For this, hold the Light button until the watch shuts off, as opposed to selecting power off. Then power this on again. 
• If this issue continues, I would recommend using the following steps to maximizing the Bluetooth connection using through the watch menu with these steps: 

1. Hold the menu button
2. Select Connectivity
3. Select Phone.
4. Repeatedly press your top left button. (It will be about 5 times.) A hidden menu will then appear.
5. Toggle the Maximize Connectivity menu to On.
6. Open your Connect Mobile App and manually sync your watch.

Then test the pairing again with the phone.