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

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

• 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