Versa Lite stopped syncing with iphone7/bizarre sleep scores

[NJ55]

After 18 months my Versa Lite suddenly won’t sync with my iphone7. 
I’ve done everything:

toggled Bluetooth on and off

restarted 

reinstalled app

tried to set up as a new device (that stopped working half way thru process!)

For last 2 weeks it has told me I’d only slept for approx 5hrs a night which was a worry-now am wondering is it another glitch to add to the not syncing. 
Is it a coincidence that I upgraded to premium at the same time?

Have never had a problem with free account. 

[EdsonFitbit]

Welcome to the Fitbit Community, @NJ55.

Thank you for informing us about the difficulties you experienced with your Fitbit Versa Lite and for the troubleshooting steps you’ve performed.

To resolve syncing issues, we recommend following these instructions.

Some users have had success setting their Fitbit devices to track sleep in a sensitive mode. For information about how this setting works, please visit this site and open the menu "What's the difference between the normal and sensitive sleep setting?".

In addition, you can restart your Watch by following these steps.

Hope this helps.

[NJ55]

Sent from my iPhone

[EdsonFitbit]

Thanks for your response, @NJ55.

There is no information in your reply. It's just blank.

If you still need assistance please let me know.

Have a nice day.