@Angepops Welcome to the forum. What's your phone model and OS? For now, please try this:
The trick here is to not pair in phone Bluetooth settings but rather let the Fitbit mobile app do that.
Additional tips if sync issues persist: If you have Wifi set up, go to Fitbit mobile app and remove it, then sync your Versa. I noticed that it causes issues for me. If you have other Bluetooth devices paired with your phone, forget them. One of them might be causing issues. Also, make sure Always Connected (if you're on Android) and All day sync are enabled.