If you can, install and use the SimpleCheckUp app.

• It can always tell you when the watch last synced,
  
• It can always tell you if the watch can talk to the phone.

1. try restarting the watch.
2. try restarting the phone.
3. try logout of the Fitbit App [you will need the password to login again, if its not saved on the phone].
4. On Android, login to the Fitbit App, go to the phone's home screen without closing the App.
5. Click on the popup sync notification and wait for it to pair and link.

If you can, install and use the SimpleCheckUp app.

• It can always tell you when the watch last synced,
  
• It can always tell you if the watch can talk to the phone.

1. try restarting the watch.
2. try restarting the phone.
3. Make sure the phone is not closing either Bluetooth or the Fitbit App to save battery.
   

If you can, install and use the SimpleCheckUp app.

• It can always tell you which time zone your watch is set on,
  
• It can always tell you when the watch last synced,
• It can always tell you if the watch can talk to the phone.

1. Check your phone time is correct and is set to network time.
2. Check the Fitbit App is set to automatic time zone [Profile photo, App settings].
   
3. Check your watch is synced.

These watches have been out a year and if your watch stops charging out of warranty you may need a new charge cable.

This one from China is better made, more sturdy than the original and only costs less than $3,
comes in short cable for travel [30 cm, 1 foot] or long for home [1m or 3 feet].

The pins are longer and more firmly positioned.

It may be useful to have one on standby given the problems with the original cables.

6. Problems with specific Notifications not arriving on the watch (Android)

If after defining Notifications, App Notifications in the Fitbit App the messages still do not arrive on the watch but others do,
Consider Macrodroid - it has 5 macros free.

Of course Macrodroid needs to be added to the list of apps that messages show on the watch

7. Get phone battery state notifications on your watch (Android)

Using MacroDroid on your Android phone, which allows for 5 free macros, create one macro like this,
and in the Fitbit App Device, Notifications, App notifications, select MacroDroid

The definition process is:

Open MacroDroid
Click Macros at the bottom
Click + at the bottom
In Triggers, click Battery level, and ok in the popup
Slide to the desired level and click ok

Repeat for as many levels as you need alerts for, then

Click Actions at the top
Click Display Notification
Enter title = Phone Battery
Enter Notification text ,as shown above
Click ok
Click tick and give the macro a name

That's it !

Each time the phone battery falls to a level you have selected in your macro you will receive a message on your watch, if it is Bluetooth connectable at that time.

Of course it can be used to alert you of other events with additional macros.

• it requires an Android phone with 8.0 or greater
• it won't work with an iPhone or iPad
  
• it will require a Google account to operate it
• it only has a day battery life new, which will decrease over time
• it is waterproof, a bit - see full specs here
• no On-Wrist calls
  

• https://www.fitbit.com/global/us/products/smartwatches/google-pixel-watch

Fitbit Sense 2 / Versa 4 - released September 23, 2022 (Not recommended) :
          (are NOT upgrades to Sense / Versa 3)

• they have a different watch menus and navigation
• they don't have any Google Assistant
  
• they don't have any music functions
• no user Wi-Fi
  
• no On-Wrist calls (despite microphone and speaker, with base firmware)
  
• they don't have any integration with any other 3rd party apps
• there are no non Fitbit apps currently available
• there is no Agenda app
• there is no SOS or fall detection
• primitive alarms and timers
  
• there are very few choices of clocks currently, and non Fitbit ones may not be supported
  
• the software has numerous flaws, may reboot often or stop with a big red X
  
• the sample battery life is effectively limited to 10% to 99%
• comes with the same flawed charge cable, as on the Sense / Versa 3, may need replacing often
  
• button will not turn display on and off, only on
• steps under counted by about 10% on sample unit
  
• heart rate inaccuracy issues during exercise still exists on sample
  
• some functions of older watches no longer available
• waterproofing unconfirmed, may be same as Pixel, more accurately described
  
• Shops generally offer a 30 day refund, Fitbit ordered, offers 45 days
  

• https://www.fitbit.com/global/us/products/smartwatches/sense2

• https://www.fitbit.com/global/us/products/smartwatches/versa-4?sku=523BKBK